[Safari Larry]

I'm new to this forum so bare with me while I stumble around with my first post. My good e-friend Bill Hanlon told me about this thread so you can blame him. I am the POCI 1956 Technical Adviser. This thread is applicable to what I'm doing so here we go, back to the original intent of the thread...

I have mated a 55 std trans/clutch to a 59 engine and a 56 Strato-Flight (controlled coupling) to a 60 engine. There were no interface problems for those applications.

A friend mated a 55 dual-range (slant-pan) to a 59 engine and had the problem you guys have been talking about. Here's what he had to say:

"When I put a 59 389 in my 55 Chieftain and bolted it to the 55 hydro flywheel the flywheel wobbled and wiped out the trans front pump. The problem was the 389 had balance weights welded to the crank flange and the 287 didn't. The weights were in the way and wouldn't let the flywheel mount flush to the crank. I had to have the flywheel turned at the crank flange area on a brake drum lathe until the weights would clear, then had the flywheel rebalanced and all fit then and has been together now for 19 years"

I don't think balance weights he references were "welded" to the crank flange but was an integral part of the flange.

I recently wrote a web article on 1955-60 engine identification and interchangeability. You can find it by going to www.PontiacSafari.com, click on "Pontiac Garage", and click on "Pontiac Engine Component Interchange & Identification". That article talks about installing 1959-60 engine in earlier chassis. It also tells how to identify engine components with an almost complete list of casting numbers. I don't claim to know everything so if you find anything wrong or have suggestions for the article, please let me know.

The '60 engine pictured in that article is a reincarnation from Pontiac Heaven (small world). God (the guy with the keys to heaven) drove up in a 1961 Pontiac station wagon chariot which verified to me that I was truly at heaven's gate. I've been to heaven and it was glorious!

Regarding the missing reinforcing rib in the 1955 block. According to "Pontiac Service Craftsman News", October 1955, in talking about the changes for 1956, it says:

"The cylinder block has been made more rigid to ensure utmost durability with the greater horsepower and torque. This was accomplished by adding more metal at the three intermediate bearing bulkheads".

This may be referring to the missing rib in the 55 engine. I have a disassembled 56 block so could check for the rib if I knew what to look for.

While we are on this subject, does anyone REALLY know why Pontiac abandoned the reverse flow cooling in 1960? The prevailing opinion seems to be that there were problems with the water distributing tubes in the heads getting clogged with rust. There are other opinions and "educated guesses". I have an article on that issue and you can find a link to it in the "Pontiac Garage" page on my site.

Regarding the '56 hydramatic transmissions, according to the 1956 Accessorizer (available on my site), only the Turbo-Flight was available for the Star Chiefs and only the dual-range was available for Chieftains. I've never seen a dual-range in a Star Chief but I have seen the Turbo-Flight in an 870 Chieftain.

[stevep]

I have only seen Strato-Flites in 56 Star Chiefs. I have seen Hydros and Strato-iFlites in Chieftains. I think that the Hydro may have only been in the Chieftain 860, but I can't be sure.

[Steve Barcak]

Larry, Welcome to the PY boardanf thanks for your contribution. My understanding for dumping the reverse colling was for better packaging of accessories but, I do not know for sure. It seems logical.

Steve Barcak www.pontiacheaven.org

"Real Pontiacs only...no corporate nonsense!"

[Safari Larry]

Originally Posted by Steve Barcak

My understanding for dumping the reverse colling was for better packaging of accessories but, I do not know for sure. It seems logical.

Well, there is another vote for "better packaging of accessories". It doesn't seem so logical to me. The Pontiac Shop manuals up though 1959 said:

"The combination of reverse flow circulation and gusher valve cooling results in relatively low operating temperature of valves and valve seats. Valve life is greatly increased, therefore, and valve seat inserts are not required.

With reverse flow circulation no cooled water is thrown directly on cylinder walls to cause cylinder distortion. Sludging of engine oil is minimized since highest temperature coolants are retained in the cylinder block, particularly during warm-up, and condensation on cylinder bores is thereby reduced."

That seems a lot to give up for a small amount of space savings in front of the engine for mounting stuff. And did the '60 engine really make use of the gained space over '59? I don't think so.

I've asked John Sawruk about this and he thought it was because of problems with rust and plugging of the water distributing tubes; resulting warranty issues. But he wasn't sure either and was going to check into it.

If PMD really believed what was printed in the shop manuals, it surely would have taken a VERY good reason to abandon reverse flow.

No one seems to really know, just "I heard" or "I think".

[Bill Eveland]

Hi Larry, glad to see you posting here. Welcome aboard.

Did you ever make good use out of the clutch pedels and ring and pinion yet.

Put in in the guessing catagory for the rust issues on the reverse cooling. Weren't they having a bunch of warranty issues and thats why they ditched, of course i'm guessing again.

[Safari Larry]

Thanks Bill, glad to be aboard and good to see you here along with a couple of other familiar names that are smart about the "right stuff" (Pontiacs). I had visited this forum some time ago (years?) but I didn't find too much interesting back then. Things have changed on the forum now, lots of good stuff here of interest to you and I. Some things I like about the 1950's Pontiac Yahoo group better, some things I like about this forum better. Guess I have to watch both as you and Bill do.

I have not used the clutch pedals and ring and pinion yet. I got the pedals cleaned & parts painted but but continued work on the Safari has stalled due to other stuff that has to get done. Retirement is not all it is cracked up to be. The work is just different and still gets in the way of important stuff!

Warranty issues is one of the guesses as to why Pontiac dumped reverse cooling. So I'll chalk up one more vote for warranty issues -- which now has a slight lead. I believe I read that as a theory (not fact) in one of John Gunnel's books, something he had heard. Warranty issues could be a result of the tubes plugging up. If not, I would like to know what the warranty issues were. I don't know of anyone having any particular problem today with the 1955-59 engines that could have caused warranty issues.

I've been chasing an answer to that question for some time. I'm beginning wonder if a "for real" answer will be found.

[Bill Eveland]

I can only speculate why they abandoned the reverse cooling , i'm too young to have first hand experiance when these cars were new. I could only think now the "restorer" takes better care of their car instead of the daily driver years ago. Maybe the improvments with antifreeze has gotton better and helped with the rust concern.
One thing I've noticed on the new cars I work on is year after year on the same model they redesign or remove parts on newer models thats not really needed to save cost. Figure on a mass produced car save $10 here and there on thousands and thousands of vehicles it really adds up. Maybe Pontiac thought they could get by without the tubes and help save cost.
Or course this is just me thinking out load, some of this may make sense, some not.

[Safari Larry]

Bill, for a young whipper-snapper, you make a good point about the cars getting better care today. I worked as a mechanic in a Pontiac dealership in 1962-63. I was not aware of any problems with the '59 and earlier engines -- but maybe I just wasn't paying attention, perhaps my mind was more on the glorious back seat of my 55 Pontiac.

I've heard the cost reduction theory before. Don't forget the stuff Pontiac published saying how great reverse cooling was (see my previous post). Give up all those benefits for a few bucks in savings for engine build? I don't buy it. As I said before, if PMD really believed in what they were publishing/advertising, they needed a VERY good reason for the switch and engine problems with warranty repairs is the only VERY good reason that I've heard.

I've invented yet another theory which seems to make sense. They changed engine cooling to improve cooling around the cylinders which the switch most certainly did. Larger bores, higher compression, and thinner cylinder walls could have resulted in overheating and failure of cylinders & pistons in '59 -- and resulting warranty repairs. Such problems would likely show up primarily in stressed engines; in hot climates with AC. The temperature sensor on the reverse flow engine might not detect overheating of cylinders because water that flowed to the cylinders did not return through the intake manifold where the temperature sensor was. Looking at how water flows in a reverse flow engine, it appears there would not be a lot of flow around the cylinders, especially in the rear, and the water that did reach the cylinders would have already been warmed by cooling the heads. But I've not heard of any cylinder/piston failure problem with the 59 or earlier engines so this theory might be completely wrong.

Just what we need, yet another theory pulled from thin air!

[Pontirag]

Just the cost of a single part multiplied over an entire production run will save enourmous amounts of 55-59 dollars. The reverse flow system had several parts so the cost would be even more and ipso facto, the savings would be more. Then there is the real possibility that even some brand new cars even befor they came off the assembly line would have faults and have to be corrected. With so many parts in the reverse cooling system , statistically that possibility even if its a small percent involves many cars and therefor much time and money to correct.

Then there is the warrenty period. And remember we are talking about every Car off the line from 55 to 59. And again even statistically as a small percentage it could include a large actual number of cars. And thats before any ham fisted gurrilla starts tweekin hose clamps and other sundry parts of the system... all within the warrenty period. any one of those parts when they fail could cause an expensive engine failure.
Any and each of these possibilities could include such a small percentage of over all production that they would not even show up on the radar screen in terms of a recall or other response. pontiac must also carry parts on the shelf to service warrenty issues ASAP. the cost of stocking those parts and the inability to invest that money elsewhere is a major expense and a lost opportunity expense as well. Sure you can write it off your taxes as a business expense but nobody stays in business for long by writing off thier loss's.Pure economics...and the IRS mandates that law of the jungle.

Then there is the period of time when the warrenty has run out. All the same problems mentioned above could still occure but the cost is borne by the customer so we arrive at the customers perception of long term duribility and cost over time.

Pontiac as was any auto manufacturer was very sensitive to that. Look what happened to Packard and Chrysler during the same period. Even under warrenty the customers perception of reliability and quality is indellible. Pontiac was paying attention.
Not just to the emmidiate monitary cost but the long term advertising cost. If they had to spend alot of money convincing angry customers to return to pontiac they would not have the money to engineer the performance that sold their car. Finally it would have backfired badly to promote performance on an unreliable vehicle.

Any part or product no matter how well designed and manufactured if it incorrectly or poorly serviced and maintained or misunderstood by service personel it will fail and that will reflect on the manufacturer regardless where the real fault lies. Case in point...The GM automatics up thru the early 60's. Many transmission shops got started in the business and did very well thanks to GM's auto tranny's in the fifties and sixties.

[Safari Larry]

Originally Posted by Pontirag

Just the cost of a single part multiplied over an entire production run will save enourmous amounts of 55-59 dollars... With so many parts in the reverse cooling system...

Thanks Pontirag for the well thought out response.

However, there are few additional parts in the reverse cooled engine: (1) water distributing tube in each head, (2) Elbow/gasket on front of each head for water input, (3) generic parts, including short length of 1 3/4 inch water hose, hose clamps, and bolts. In 1960 they still had to stock those parts. None of these are moving parts subject to wear. There is the possibility of water leaks in the connections but less so than with radiator hoses.

The non-reverse ("conventional") cooled 1960 engine has a few parts that the reverse cooled engine did not have -- fittings and hose to connect water flow from intake to front cover.

If Pontiac had made the switch in 1961 when there were several engine changes made, I might buy the cost reduction theory. But they made the switch in 1960 to an engine that was very similar to 1959. This required a redesigned front cover that is unique to 1960 and modified machining of the block. I suspect the switch would have considerable development and testing cost because of the radical change in engine cooling.

To repeat earlier post, here is what PMD was saying in 1959

"The combination of reverse flow circulation and gusher valve cooling results in relatively low operating temperature of valves and valve seats. Valve life is greatly increased, therefore, and valve seat inserts are not required.

With reverse flow circulation no cooled water is thrown directly on cylinder walls to cause cylinder distortion. Sludging of engine oil is minimized since highest temperature coolants are retained in the cylinder block, particularly during warm-up, and condensation on cylinder bores is thereby reduced."

If we are to believe that, then surely the conventional cooled engine would be subject to reduced valve life and sludge in the engine. Surely the reverse cooled engine would last longer with less problems than the conventional cooled engine. Maybe PMD didn't believe it and it was a sales gimmick. I don't know.

So I still have doubts that Pontiac made the switch for cost reasons. I have doubts that they made the switch to make more room for bolt-on accessories. It seems reasonable that they made the switch because of some engine problem (i.e., an engineering change to solve the problem), perhaps valve failure because of stopped up water distributing tubes or piston failure because of inadequate cylinder cooling.

The jury is still out!

[Pontirag]

presuming thats why they did it. GM was very conservative and risk adverse when it came to warrenty. Whereas any savings when spread over many cars each year over several years would save quit a bit of money.

They went from brass coolant distribution tube to stainless in 57. Stainless cost more in every respect except one: it does not fail thus reducing maintenance and servicing cost(Under warrenty)

Total for total the number of parts may be the same but when it comes time to service one system the 59 and earlier engines requir the "disruption" of associated systems unrelated to the system needing repair initialy. Once those unrelat6ed systems are disrupted then there becomes the added risk that they may need additional work with increased cost and they also may fail if faulty service was provided again at cost thus addiing statistically to the possibility of future failure its associated cost the disatisfaction of a come back with regards to the customer and that leads back to the perception issue.

As for the unique 1960 transition engine. Logically it would seem as you say that you are right. However remeber two things GM is conservitive and risk adverse. If the transition engineering was implemented and it failed it would only effect 1 year plus they could always revert back to a previous and provin design. If they made too many changes all at once and any one of them failed and it could not be corrected easily then they would be in dire streights warrenty wise and again customers perception. Plus any competator would not let them live it down. Not quit as bad as a Stalinist purge but ...
As for the longer engin life. That may be entirly possible but the source for all that information is advertising, dogma and propaganda. Check out SAE for suportable evidence. Not to say its wrong one way or the other but Check the source and its intended purpose. Many many engines manufactured by many companies relied on the distribution tube method. it did work.

As for the cost deal. GM was in business to make money. they had to answer to the stock market for success or failure. Any reduction in cost even pennies when multiplied over several brands, over several models, over several million cars , over many years it adds up enoumously.This is 1950's dollars too which is difficult to put into perspective nowadays but remember annual income back then was about 5000 pr year. If you can save 2 bucks per car anywhere in the system in a single year that a million buck a year. And those are the numbers you can crunch. Warrenty work will break you in half. Again look at Packard during the same period. It killed them. Chrysler was never actually ever able to recover its image after ist 50's quality debacle. They were still dying a slow death up until Iaccoca rescued them. Its all about the money.its only about the money. only a pimp or a liar will tell you different. Its all about the money because Money is the only universal unit of measurement used across the board to measure the efficincy, success and performance of any dimention of the industry. Any industry! Cost= Money.

[Safari Larry]

Originally Posted by Pontirag

GM was very conservative and risk adverse when it came to warrenty. Whereas any savings when spread over many cars each year over several years would save quit a bit of money.

Maybe so for GM but I don't think Pontiac and Bunky Knudson were conservative and risk adverse. The stainless in the tubes was a small percentage of the total stainless in/on the cars.

Originally Posted by Pontirag

Total for total the number of parts may be the same but when it comes time to service one system the 59 and earlier engines requir the "disruption" of associated systems unrelated to the system needing repair initialy.

Disruption of the reverse cooling hardware for "associated systems unrelated" means removing the connection to the heads for something like replacing front seal or timing chain. There if very little risk to reconnecting those connections. Plus the '60 engine has it's own minimal "risks" that the 59 engine doesn't have.

Originally Posted by Pontirag

As for the longer engine life. That may be entirly possible but the source for all that information is advertising, dogma and propaganda. Check out SAE for suportable evidence. Not to say its wrong one way or the other but Check the source and its intended purpose. Many many engines manufactured by many companies relied on the distribution tube method. it did work.

The info that I quoted about the reverse cooling benefits came from the Shop Manual which was not generally available to the public. It may have been dogma and propaganda but directed to service personnel, not the the public. I would not call it advertising unless it is in an advertisement. I've seen it advertised in 1955 ads but don't know about later years. I don't pay much attention to advertisements after 1957.

Originally Posted by Pontirag

As for the cost deal. GM was in business to make money. they had to answer to the stock market for success or failure. Any reduction in cost even pennies when multiplied over several brands, over several models, over several million cars , over many years it adds up enormously.

To put cost/savings into perspective, I think when you need to look at it as a percentage of production cost or profit, not as dollars. A hundred thousand dollars is a LOT of money to me but as a percentage of billions, it's not much.

You may be correct but at this point, it is speculation. If you are correct, why did Pontiac use reverse cooling in the first place, back in the true "conservative" years (pre Bunky)?

Here's what John Sawruk said "I was told at work that the water tubes both rusted out & plugged up." John worked as a tester, engine designer, and executive for PMD. I doubt that the stainless tubes rusted out but may have been plugged up by rust.

[Pontirag]

gm avoided risk as would any corporation read anything written by any of the CEO's from sloan to wangers . So its not actual an opinion. Its the corporate culture. Bunky was past over for promotion and quit. wangers was ousted after Delorean went to Chevy. Delorean himself never got past chevy. Pontiac began designing that v8 back in 48. seven years to develop it and with so many other examples to emulate. Thats pretty concervative and rightly so. If they had failed...remember Bunky brought them back from the edge just like his father did with buick a generation before. Of course it did not and here we are. Bunky knew and stated so in an interview that if he failed to reviev Pontiac (this was in 56 not 54) it would be gone and so would he. Wangers said as much in his book. It was risky.. to his career. the engineer got it right such that by the second year of v8 production they had dual quads and were winning races.


Re read the portion about the distribution tubes. The choice to install stainless was the least risky of the choices. Dont know if i made that clear.the other option was rusty and clogged tubes. eliminat the rusty tubes and most of the problems were solved thus reducing the need to go in and disturb a system which may result in additional warrenty expense. it was the least risky choice until the new cooling system came on line.There are risks to servicing those related components. broken bolts, cracked housings, stripped threads tweeked hose clamps that cause leaks. each step required to service a component has risk and therfor cost. eliminate the step by reengineering and you eliminate the risk and therfor the cost. think it thru and there is no arguement.Take alook at commercial aviation. Its a science.


As for the advertising, propaganda, dogma perhaps I should have said Hype. all the same kind of adjectives really. several resources describing new features on cars overstate there qualities not that there was a down side but mechanics as are all of us are a little conservitive when it comes to change. but from a marketing perspective you cant state that yesterdays design is bad and todays is good or you've just dis'ed all your previous customers. Its always new and improved. Its only better than the competitions model never last years model.

plus mechanics are familiar with the old and regardless what any one individual says last years technologydid work and properly serviced it worked well. That was not the reason they changed it. It all goes back to warrenty costing and servicing. With all due respect to Mr Sawruk. "Thats what he was told". Its hersay then and I am certain quite true but If a stainless tube clogs up isint that even the slimist of possibilities .. a service or warrenty issue.

brochures are hype to customers, service manuals are, in there own way hype to sell, reassure or convince the creature of habit AKA the mechanic. I also got GM manuals, there is some hype in it. Dont believe me? fine! but take a look at Military or aviation maintenance manuals. Very sterile. Besides ask youself or any one else in this hobby/industry arnt we all a little(?) conservative or why would we be fondly reminicing and reliving out past in such glorified steel. Take one look at the marketing to Our hobby. We pay big bucks to be comforted in our past. Sounds pretty conservative to me.

"cost savings" is money. "percentage of production cost" is money. "profit" is money. "A hundred thousand dollars" is money, "as a percentage of billions" its still money. I did not say billions but I did caution the reader to put it in the perspective of 50' s dollars. and that being so it is indeed big bucks which goes right back to MONEY. Money to fix existing problems. money to engineer solutions. money to market to customers. money to cover warrenty's Money to train mechanics to service the new and improved.Money to keep parts on the shelf, Money spent here which could have been spent their. Money money money.

Why did they use reverse cooling back then? because it worked not just for GM but ford and mopar too. Its not speculation in the sense you refer to. it was an investment gamble that paid off. Back to the money.Its not even "speculation" in the sense you imply either. GM biography's. courses in Logistics, University level Maintenance management programs put all of the above quite a ways beyond "speculation" Its not even a rairified art form. Its a formal science backed by statistical analysis.



Finally....Why do you think everybody complains so bitterly about accountants designing cars we drive today. Because it became too much about money. It should never have gotten to that point but it did and even though we agree its about money we still cant even get that right.

[Safari Larry]

Thanks for the Pontiac history lesson. I'm not clear on what the bottom line is. I believe you are making the argument that the switch from reverse flow to conventional cooling was based on reduction in cost due to the elimination of the distributing tubes and on reduced maintenance risk because of elimination of the water passages connecting the front cover to the heads. Is that correct?

Whatever you are suggesting, is it what you know be fact or is it what you suspect based on logic, reasoning, and knowledge of PMD risk analysis processes?

[Pontirag]

I dont teach history. I teach, but not history. It was not my point to be made. If it came across argumentitivly, I opologise. I was simply trying to explaine that engineering evolution does not come from reading tea leaves in a cup or studying cat guts on the hiway shoulder. its actually a well founded science...now. I was not clear on the bottom line either so I contributed some facts and information to help form it out....a little.

It was stated that there were issues with this cooling system of the mid 50's pontiac and that this system was abandoned. I'm suggesting that the cooling system evolved. The fact that we have come full circle and now GM is implementing a variation of the system again suggest(Gm's actions suggests, not me ) that it was not a bad idea in theory, just difficult to maintain with 50's technology (difficult as in costly).

Currently, in other parts of this forum, pontiac vehicle owners are experiencing overheating conditions in their cars. They are, in lite of GM's latest rendition of the technology, re-evaluating their cooling systems and trying to re-invent the reverse cooling system in there cars. To a lesser or greater extent they are selecting certain aspects of it and experiencing degrees of success. But, clearly there is a lack of understanding of the theory and technology to adapt the system in total. I am curious just how much of GM's current system reflects that past precidence. It might just be advertising hype!

It was also stated that GM abandoned the system in favor of another. It was actualy an natural evolution. A transition.

I know my facts. Of that I am at least certain?!?That which I dont know I rely upon the knowledge and expertise of others. It not speculation or opinion. Logic reasoning and Knowlege are the very firmist foundation for any analysis. Subject area expertise and an understanding of statistics would be others I would add to your list.

Taking an informal survey of the vehicle owners opinions of GM engineers reasoning 53 years ago based on their (the owners) current ownership of a 55-59 pontiac is like evaluating the eating habit of Americans by assessing the contents of a dumpster behind a McDonalds. Some correct conclusions might be drawn but you will need to allow for some error.

It is an interesting subject, certainly in lite of GM's choice to use a variation of it on the hi performance premier show boat, the corvette. It validates the actions of the engineers 50 odd years ago and reaffirms the correctness of my choice to own a Pontiac...or two. It is indeed a fasinating subject that would help us all understand more fully the inner workings of our own cars, Pontiac, and GM.

Rather than speculate and opine. Sombody should dig up and dust off the engineering records and data and maybe the inter office memos regarding this subject and share it with us. Thats my suggested opinion.

class dismissed. Quiz on friday Dont make me call your parents!

[Bill Eveland]

Don't you guys think the tubes were just a carry over from what they were already using? The distribution tubes go back well into the 30's. I don't have any info past then for earlier use.

If they were already using the tubes in the earlier stuff and had problems clogging with rust they would have got rid of them sooner or redesigned them than don't you think for the rust clogging issues, unless it was the design change to use them in the v-8 instead of an L-head engine that made the differance.

[Safari Larry]

Good point Bill. I'm not familiar with the pre-55 Pontiac inline flathead Pontiac engines and didn't know they used a tube like the V8 engine. If they had used the tubes for years, it would seem it was proven hardware -- and would make it seem less likely that the tubes would plug up in the new V8 -- and adds doubt to the theory that plugged up tubes was a reason for the cooling design change in 1960 (or design "evolution" if you prefer to call it that).

Regarding the suggestion that "Sombody should dig up and dust off the engineering records and data and maybe the inter office memos regarding this subject", such records don't exist. Very few Pontiac records exist prior to 1961. I read somewhere that there was a fire that destroyed many of the records.

[Steve Barcak]

Larry,
I just saw where you are from and wonder if you are the same person who bought a '60 389 from me a few years back to put in a Safari? If you are not the one, someone from Lancaster bought a '60 389 from me here at Pontiac Heaven a few years back. He said it was going in a 2 dr Safari. If not you, you may know who he is.
Speaking of Safaris, we had a few show up at my 10th annual Pontiac Heaven. This '55 came from Montana.

Steve Barcak www.pontiacheaven.org

"Real Pontiacs only...no corporate nonsense!"

[Safari Larry]

Steve, you got me pegged, I am the person that bought the '60 389 from you, in Oct 2004 I believe. The engine is now in my '56 Safari but I still have a lot of work to get the car back together -- and other stuff is getting in the way so progress is stalled for a few months. I have restoration photos posted at www.pontiacsafari.com/MySafari/ and earlier restoration photos at www.pontiacsafari.com/My56Safari/.

I had the engine rebuilt and balanced. One cylinder didn't clean up at .030 over so they sleeved it. I have not started the engine yet. I know a lot more about the '60 engine now. I previously thought the 59 & 60 engines were the same but not so.

I considered going to Pontiac Heaven X but it wasn't in the cards. Maybe next year. It appears to be an AWESOME event.

Sorry for messing up your original thread. I should have started a new thread on the reverse cooling change. Being new to this forum, I can plead ignorance.

[Jack Gifford]

Larry- welcome, and thanks for restarting the reverse-flow cooling discussion. At least a couple of times, I've posed the question of "why" on these forums, but didn't get any factual information. Although I started driving in '56, not many people around me had new Pontiacs, so I'm not aware of whether inordinate cooling system problems occurred or not. From '59 through about '87, I built and ran a fair number of pre-'60 Pontiac engines, and didn't experience any cooling system problems- even in a 3/16" overbored '57 with 13.5:1 compression ratio. True, the stock radiator in the '60 Falcon had to be replaced with a custom crossflow unit, but that's just basic physics. A similar engine never overheated with the stock radiator in a '57 Chev- even during a couple of hot-laps of Germany's Nuerburgring- all 27 Km of it.

I've been leaning toward the room-for-accessories explanation, but I hadn't really taken note of your point about '60 engines not utilizing the new free space.

I've also tended to suspect that PMD realized that the "benefits" (reduced sludge, longer valve/seat life) weren't actually required- what with improvements in engine oil, etc.

I trust that eventually the answer will surface.