[Stan65]

So what I want to do is a basic rebuild. Want it to appear and sound original. So 4X-H1’s, intake, carb, distributor, and exhaust manifolds will remain. Want to go roller cam for dependability. So what’s everyone’s thoughts on what to replace, reuse, and upgrade.

I know the answers will be all over the place. I searched for a couple days and most rebuilds have upgrades that take away from the original appearance and sound.

Here’s my new to me Brewster D-port auto.

Thanks in advance,
Stan

[steve25]

The first to do is to get the heads check out for cracks, or even the start of a cracking issue since the 4 series heads where prone to that.

Your motor originally was fitted with the 067 cam if I am not mistaken, and if so then that small of a cam might mean getting a custom hydro roller ground up.if you want to as you say,stay real close to stock.

[mgarblik]

I will jump right in the deep end. You stated stock rebuild, stock look, sound and I assume performance. I see no need to replace anything with non-stock type parts to get the results you listed. This includes the switch to a roller cam. Why spend over $1000.00 extra to gain nothing? If your really worried about the camshaft wear, have your new flat tappet cam nitrided. You can re-use your stock connecting rods with new rod bolts. You can install stock replacement cast pistons in the size required. The single key to success is finding and using a really good machine shop that will actually do everything properly the way it should be done. That's the bottom line. When these engines were built the first time at PMD, they didn't use any expensive exotic parts. But everything was clean, properly machined and verified for a correct assembly. Heads already have hard seats. Probably need a set of guide liners and a quality valve job. Deck squared-up, line honed, nice torque plate hone and your done. Should make 240-250 HP and be stone reliable with about a 5000 RPM red line. So that's the basic stock rebuild. Probably about $1200.00 worth of parts. By the time this thread is over, I bet some will suggest $6000-7000 in parts to make about the same power. Hope you get some good ideas.

[Stan65]

Agree on the magnaflux. The block and heads are at the machine shop now. I don’t need to stay with the OEM cam specs, or compression for that matter. Just needs to appear and sound stock. I want a clean burning idle. I have hopped up cars already. I want to “restore” one for a change.

Thanks.

[Stan65]

Mgarblik,

I will never build another engine with a flat tappet cam. My cars sit for long periods of time and the dry restart gets them most times. I have tried several things in the past to make them live. Comp zink additives, redline oils, even went as far as pulling inner springs and pre lubing. Just not worth it to me.

$1000 for a roller setup is already in the budget. Not trying for a budget build.

I’m looking into the Howard’s LS lifters and the ford spider/dog bones. link bar lifters won’t fit under the EGR style valley pan.

The comments I am expecting are exactly what you are expecting. New rods don’t cost much more than magging, straightening, new rod bolts, and resizing the original rods.

I am all for a little more compression and a little more cam. Just want a smooth idle and gobs of torque.


Thanks again. Keep the replies coming.

[Formulas]

Those particular heads are about 115cc right?

I would be hard pressed to reuse them when 94 cc and 101 cc heads are abundant and wouldnt bust the appearance except for codes

your heads would need a heavy mill just to make half way decent compression

doesnt Butler offer baby rollers for near stock valve events?

[hurryinhoosier62]

You’d be better off with 6X-4 heads. To echo Mike, finding a COMPETENT machine shop is the crux of a successful build; if they start telling you to “trust them” run like hell! I have seen too many guys on here start the “It’s just a street engine” mantra when we engine machinists attempt to give them advice.Unless you have thousands of dollars to waste keep it simple. I haven’t seen a set of the Chinese forged rods that didn’t need a bit of “touch up” work on the small end or the big end. You can’t go wrong with Molnar connecting rods. Haven’t used a set, but all of my machinist buddies swear by them. Find a GOOD crank grinder who understands what being “on stroke” and “on spec” means. As far as roller cams, realize that cam billets are still in short supply. Don’t let anyone try to talk you out of using the OE iron intake; they are a good street intake manifold. Wash everything thoroughly, assemble carefully and grin every time you open the throttle!

[mgarblik]

Once you have had a bad experience with wiping out a flat tappet cam, I can understand the worry. Make sure your roller lifters of choice are up to quality standards as well. I have had plenty of roller lifter failures as well, but not many in the low spring rate, street stuff. Connecting rods, certainly there are much better choices than stock PMD, but they will need to be checked carefully and possibly touched up some. There are certainly many iron heads to bump up the compression some. A camshaft with modest lift in the .450 range and wide lobe separation range, 113-115 will get you the sound and smooth idle/big low end torque you desire. Good luck with the build. Of course all of the changes I just mentioned in this post move away from the "stock rebuild" you listed in post #1. I have also now at least tripled the cost of your rebuild from my first post and maybe gained you 25-30 HP. In the end, we all know the formula: How much power do you want to make? How much $$$$ do you have?. It is all fun though.

[Lee]

I have a '73 T/A clone. 455, with similar spec "66" heads. I used the KB347 pistons, which have just enough "dome" (a slightly raised pad, more accurately) to zero out the valve relief, which give me a final CR of 8.3:1. Scat rods connect them to the stock crank. I designed a low lift cam (see signature) to be able to retain the stock non-adjustable valve train. I'm using a P4B intake with FAST EFI/ignition, but results would be similar with a well built Qjet & HEI. I do have headers (tri-Y) and a low restriction exhaust.

Anyway, it has made ~ 315hp/385tq at the wheels, and ran 13.1 with 3.08 gears & a stock stall, all on 87 octane.

[PAUL K]

Originally Posted by mgarblik

Once you have had a bad experience with wiping out a flat tappet cam, I can understand the worry. Make sure your roller lifters of choice are up to quality standards as well. I have had plenty of roller lifter failures as well, but not many in the low spring rate, street stuff. Connecting rods, certainly there are much better choices than stock PMD, but they will need to be checked carefully and possibly touched up some. There are certainly many iron heads to bump up the compression some. A camshaft with modest lift in the .450 range and wide lobe separation range, 113-115 will get you the sound and smooth idle/big low end torque you desire. Good luck with the build. Of course all of the changes I just mentioned in this post move away from the "stock rebuild" you listed in post #1. I have also now at least tripled the cost of your rebuild from my first post and maybe gained you 25-30 HP. In the end, we all know the formula: How much power do you want to make? How much $$$$ do you have?. It is all fun though.

In addition a roller lifter failure can destroy the block and do considerable damage. A flat tappet failure may cause a teardown and inspection but I've never seen catastrophic damage from a failure.

[PAUL K]

Looks like a great project. Wanting my 73 Trans Am to sound stock, look original, retain most of the original parts and perform better than a Super Duty this is how I built mine.

The block was the hot tanked, checked, bored .030 and torque plate honed. I used a set of old TRW domed pistons that put the compression ratio close to 10:1. Original rods were rebuilt using ARP bolts and the original crank was used. The rotating assembly was balanced. Cam was a HFT 231 @ .050 duration .540 lift. The original heads were converted for screw in studs, ported to flow 240/180 and the exhaust crossovers filled. The original intake manifold was ported and the EGR bump under the secondary barrel was removed. The original carb was restored and the recalibrated. The original distributor was modified for quicker advance, the vacuum canister travel limited and a Crane electronic conversion kit was installed. I was lucky enough to find a set of H-O racing specialties tri-y headers. I used those with a mandrel bent 2.5 inch exhaust system using two walker bullet mufflers located where the resonators were on a 73 SD car and a high flow crossflow muffler with OEM tips.

Things I might've done differently..... Find a pair of 4X heads from a 400 with a similar date code that already have screw in studs. This would save the expense of converting the heads to screw in studs and allow a decent compression ratio with flat top piston and 87 octane fuel could be used. Reprofiled the cam to work with less compression and give the car a true "stock" idle sound....now it has a little bit of a rumble.

[steve25]

The details I have found for the OPs motor are 112.3 for the chamber volume which makes for a 8.2 to 1 compression.

The cam indeed was the 067 grind, rated Hp was 250.

[Stan65]

Thanks everone thats responded so far!

My 4X heads do have factory screw in studs.

I suppose I should have been more specific in my first post. I am keeping all the original exterior parts as it will be a correct restoration (if they pass the magnaflux inspection). I would like bullet proof reliability by upgrading the "failure points". Examples I am aware of the flat tappet cam / lifter failures and I hope the lower lift and duration along with a non link bar lifter being lighter combined with a low rpm ceiling will make a roller last like an OEM roller engine. I am also fully aware of the factory rod bolts that are 50 years old so at a minimum I would replace them with ARP (which of course requires rebuilding the rods). While doing so if I can gain more performance that would be nice also. I also completely understand the intricacies of machining. I haven’t built a Pontiac for about 25 years, but its not my first. When I was building them the aftermarkets parts were super expensive or nonexistent. The best I could hope for was a set of SD rods and a N crank.
What I hope to get out of this is: “These” pistons with a 0-.010 deck and this head gasket thickness will get you the desired quench distance (.040"-.060". They will also increase the compression to roughly “x” if the heads cc to the original 115cc. (I understand changing to 6x-8’s is a huge improvement, but I really want to stay original).
I’ve also read up lately about that Pontiacs want for lobe separation with the low rpm torque-based design, and see that 112-116 degrees where 114 is probably a sweet spot.

Also included a couple pics of a 409 I’m building so everyone gets an idea of my capabilities.

Once again thanks all who have participated.
Stan

[johnta1]

Stuart, with the bigger cubes of the 455, your cam selection can be more than what a 400 would take. It would not sound as radical as in a 400.
I ran a pretty large roller in my SD engine and it wasn't much different sounding than the stock cam. With the higher CR later on, it was really nice.

I'd also talk to Lee, he probably can get a decent cam for you?

Hopefully I will be able to see it next year when I get up there again.

[Douglas Willinger]

GM, how about newly cast SD 455 heads!

Make some extra funds from what your corporation has already done the research and development.

Better yet, make them with 96 cc or 87 cc chambers.

[steve25]

Doug, if I am not mistaken all the tooling and molds that GM/ Pontiac had for producing V8 motors was put up for sale in 89.

Even if Pontiac was not a defunct car line they probably could not stamp out a valve cover if they wanted to!

[PAUL K]

My heads CC'd a tick below 114. Not sure how to answer your question about deck height using a certain piston. Normally that's figured off of a blueprint dimension. Factory pistons usually sit .008-.012 in the hole on the 455's. Factory head gasket was .055 thick. The Fel-pro 1016 is .039. Pontiacs inherent issues, if there are any were the nylon gear timing chain sets which disappeared by 1973. I also feel the the lack of positive valve guide seals are easily improved. Another issue was the design of the rear oil pan seal used in 73. A nice upgrade would be to use a newer pan with the better seal but that would not fall within your guidelines of using the OEM parts.The 067 with 1.65 rockers would be an excellent choice for your goals. Personally I don't feel there is a happy LSA for any engine. Once the correct timing points are figured out for the combination the LSA ends up were it needs to be.


Those 409's are fun engines to build.

[Stan65]

Paul,

I’ve spent the last 15 years living the “W” life. Lol

A couple quick 4X questions.

Anyone know a maximum safe be distance you can cut the spring seats if I need too? Also how deep is the induction hardening on the seats?

Thanks again and another couple pics of my 09’s

[Lee]

Originally Posted by Stan65

Paul,

Anyone know a maximum safe be distance you can cut the spring seats if I need too? Also how deep is the induction hardening on the seats?

Thanks again and another couple pics of my 09’s

There is a set of Ferrea valves for sale on here right now. Using those should give you about 1.700" installed height without any cutting.

[Jay S]

Cool W engine projects Stan. We have a 62 Impala project with a W. They are cool looking engines, nothing out their like them.

For what is described I would spend a little extra cash and hunt for an OEM NOS 068 cam somewhere, and OEM NOS lifters, or old NOS Johnson lifters, or have yours refaced. I would not be afraid of a new cam, but your better off with old lifters. There would be no reason to pull the inners springs on it. The NOS stuff bypass’s ALL the current flat tappet problems. Then put 1.65 rockers on that, good flat tappet type oil(A lot better than oil in 1973) and that honestly will out last what your talking about trying, or really any other roller I think you could do. That would sound stock and run good with how the engine is described.

Some of my cars set for year at times. I worry much more about my roller cam cars that sit than my 40 year old builds with flat tappets. Todays parts are really a crap shoot on a lot of fronts, I wish the HR cam solved everything, but it really just solves one and adds more. I have a roller cam in my 77 TA, more in the spirit of Paul K’s build he described.

I am not against rollers at all. I even have had the dog bone set up mocked up in a Pontiac. What Is the Howard’s part number, are they like 2148 seal powers? All the LS lifters have the oil bands mismatched pretty bad in a Pontiac, you have to really run certain cams, but I have never seen what Howard’s are. Gaterman are the closest, but hard to find. Howard’s sources their lifters from someone else.

If you want to stay the HR route, Comp evolutions might be worth a try. Johnson have a decent rep. Most HR set ups will be quiet if you don’t get an aggressive profile. Find a profile with 55* or more of intensity from .006” to .050” is a good start to add extra life. Marine type grind. Most everything off the shelf is 52* to 53*. You probably need something pretty custom.