[Jay S]

I am going to start a thread for my W72 4 speed build. I had a lot of pictures at one point but can’t seem to find them now. But I have some pictures I will share, with more to come, including performance numbers, and show some of the mods I have done to the car. The car retains all it’s original drivetrain, which was a 200 HP W72 400 engine package with a ST-10 4 speed and 3.23s. It has fairly standard options for T/A’s in my area, PS, PB, A/C, rear defrost, firethorn red deluxe interior, and sterling silver exterior. Overall it is still in nice shape, with about 94,000 miles on it now. It has been repainted once, to a charcoal gray with black graphics. We do all of our own repairs, and paint and body work at our own shop. If the thread last long enough it will likely catch the repaint back to the factory silver.

Back when I first bought the car it hadn’t seen much love for awhile. It took a lot of little repairs to get the car so it was a dependable driver. Still have some things to do, such as the dash lights still don’t work and it is missing some ducting on the A/C. It ran pretty well though, my wife even drove it to work for a month while I worked on her daily driver. It was not particularly economical to drive, took some cranking after it set to get the qjet fired up, and 12- 14 mph was about what it averaged for fuel milage. It seemed to be dependable, at least until the heat core started leaking. I bypassed the heater and some how got an coolant air lock up in engine and it overheated, was pinging rather badly and hammered out a rod bearing. It happened after 20 miles of driving, with even a cool down in between before hand, I thought it was in the clear. So I had the stereo cranking and didn’t hear anything except the radio, until the noise was loud enough I heard it over the radio. About a mile from home I heard the rattling, and I looked down at the gauges and noticed it was overheating, I pulled off the road and shut it down….But it was too late. Funny thing was after it cooled down it still was not very low on coolant. I let it cool down, added a 2 qts of coolant, and drove it home.

Anyway, that is a little of the back story to what led me to these engine mod’s I did, and now have. My goal has been to retain all the original parts on the outside, including the 6x heads and factory egr intake, and only modify the engine on the inside. I will add the specs in my next post. I have and have had quite a few pretty fast street and drag cars, several low 11 second cars, a couple in the 10s. A couple turbocharged combos, but most the combo’s are fairly high compression (10-12:1 scr) naturally aspirated pump gas combos. I don’t beat on this one a terrible amount, it is more a fun cruiser. If it can run in the mid to upper 11s I am pretty content. I may have over shot that here initially with 550+ hp, but I would like nothing more than have to take off the headers and run log manifolds to slow it down. Hopefully by the end of this thread the car run deep into the 11s with it’s glorious (I am being sarcastic) egr goodies and looks something like this:

[TAKerry]

Looking forward to your build. I have the same motor in my 79. It has been in the shop for a rebuild going on 15 months now. I have been told its almost finished. He did some upgrades to boost the h/p as well. Curious to see what you do with yours.

[Jay S]

Some more in depth cam tech, or numbers behind the madness.

Most people on the forum would pick this 10:1 455 with stock 6x heads and a Melling RA 4 cam for a good pump gas combo over our T37 with the 10:1 SCR 455 280 cfm fast rate SFT cam, or my 11:1 Trans Am engine with the roller and the 292 cfm 6x heads…. Look how close the pumping calculators are on these. Only a 1 point octane spread between all 3.

We check the actual intake closing on cams after they are installed, based off of .009” at the valve, which with 1.5 rockers is .006” tappet lift. I have Stan Weiss’s CARFOR program that has a calculator that figures pumping compression. It also has a calculator that uses the pumping compression to calculate a fuel octane requirement, great tool for the stuff we do with engines.

For fun I will add some number’s from Wallace’s dynamic compression calculator, another calculator, among many from Wallace’s site I use a lot. I think the Wallace’s calculator uses a different cranking compression coefficient, but it adds another dimension to the pumping compression. The V/P index is the volume to pressure ratio at the point of the intake closing, giving an indication of the engine’s low speed characteristic’s for the intake closing for the DCR parameters. It is a reflection of the cylinder pressure as the valve closes. It is the number that can through all the numbers off, it doesn’t always follow the cam numbers. Of all the numbers the calculator’s produce, it is the most dynamic indicator.

Numbers for the very Popular RA4 cam, Melling SPC-8, in a 455 set up for 10:1 compression.
Installed at 109*, 77 closing
Pumping compression 173 lbs/in2
Dynamic compression at sea level= 7.2
1000 ft DCR altitude adjustment 7.0
Adjusted V/P index=129
Minimum Octane requirement= 90.6

T37 engine, 455 with 10.0 compression, ported 96 heads, Compcams Max Area Solid flat tappet. 283 intake, 291 exh, closing calculated after lash, .009” at the valve, installed at 108, 75.5 closing
Cranking Compression = 176 lbs/in2
Dynamic compression = 7.31
1000 Adjusted DCR = 7.11
Adjusted V/P index = 134
Minimum Octane= 91.3

461 Trans Am engine, 461 cid, 11.1 compression, ported 6x-4, 300 intake 308 exhaust, after lash, .009 at the valve. Installed at 111, 84 closing
Cranking compression= 178 lbs/in2
Dynamic compression= 7.37
1000 ft Adjusted DCR = 7.17
Adjusted V/P index= 123
Minimum Octane Rating=91.7

[5th TA]

Looking forward to hearing more and seeing some photos!

[Hesster1977]

Following your thread closely, love the pics and tech info - we can always learn something new.

"Stock Intake flow 6x-4, measured on our flow bench converted CFM @ 28”
.100”. 83
.200”. 138
.300”. 189
.400”. 213
.500”. 216


As to the flow numbers, as I post some old articles from my Pontiac archive stash in a couple of other threads, I came across a interesting one on Pontiac Cylinder head specs and flow numbers. See the attached article from the Pontiac Mag dated June 1991.
BUT - they state that their testing was done at 12" of water?
You are in another league than many of us, but maybe enlighten us on flow testing parameters, and some reasons why your stock results are quite a bit greater than those in the article?

Interesting you stuck with the 6x's for a stock look, but massaged the heck out of them for performance. I took a different route, went with #12's for higher compression, and competition ported them per HO specs. Never flow tested them, but gotta believe - and the point is - taking the time for proper porting can yield significant flow and performance improvements.
Hell - just compare your ported results to the stock flow rates!

[Jay S]

After 15 months I am sure you will be ready to get your car going again. I worked on this off and on for 2 years to get it how I wanted it.

Engine specs: with all the secret squirrel stuff

Compression is 11.1 SCR, 91 octane pump gas
4.155” x 4.25” stroke,
Factory 455 N crank, surface imperfections removed, and balanced
Offset ground to 4.25” stroke
RJ resized to 2.20” BBC
MJ cut to 3”, shimmed Olds thrust bearing
Clevite full groove H series bearings, oil hole opened up for full oil flow
Main girdle that connects to pan rails
Milidon 7 qt pan
King rod bearings
Scat 6.8” H beam rods
Bored with a tq plate

JE, ceramic coated, gas port 12cc domed pistons, .043”, .043”, 3/16” rings
Block is squared, decked, and line honed for ARP main studs
60 psi pump with Teflon coated gears, milidon pickup

piston to deck height is .015”
.039” felpro gaskets.

6X-4 heads, fully ported 192-194 cc port volume (stock was measured between 148-152 cc), New exhaust seats and 5.11” length 1.77” ferrea’s SS valves, Manley 2.125” x 5.12” race SS intake valves.

I will post the flows numbers for the full range, but Max flow is 292 cfm @ 28” intake and 224 cfm @ 28” on the exhaust all it by .6” lift. Center exh ports are raised .5” at the head bolts.

Bullet SolId Roller Cam, 300* 308* @.006”, 245* 253* @.050”, .3823” lobes, ICL is 111* . Cam LSA is 114*.

Morel solid roller lifters with pin oiling, .003” lash intake, .005” lash exh, Compcam 928 valve springs, 170 seat pressure, 1.85” installed height, 10 degree locks and steel retainers.

Crane gold 1.65 rockers, .631” lift max net lift.
Comp cams hi tech 5/16” pushrods
BP 7/16” rocker studs

Factory 850 cfm qjet, Cliff R mods and jetting done by me. Ported stock egr intake (in progress) I have been running a ported torker in the mean time.

DOUG’s 1 3/4” headers, 2.5” X pipe with exh cut outs

Trans: stock ST10 with a billet midplate, dual friction clutch

[SD455DJ]

Nice build Jay! Following as well. I like it with the Honeycombs!

Dennis

[Jay S]

Flow bench to flow bench can vary some, and generally do vary. The standard flow rate depression is considered 28”. Not many have a bench that will flow that much depression, they are generally always adjusted to 28”. Here is a flow conversion calculator

http://www.wallaceracing.com/calcdchg.php

For better flow comparisons between Pontiac heads, use this source:

http://users.erols.com/srweiss/tablehdc.htm#Pontiac

Pretty sure those numbers in that article came from Pete McCarthy’s testing. I have heard a couple different opinions on that. To be honest, I don’t think any of those flow’s from the testing back then are really compare to someone else’s flow bench at all. From what I recall shortly after all those Pontiac head testing were done the owner of the flow bench that did that testing found a big rat’s nest in the bench, if that was true, it made all the numbers a bit wonky. It took quite a bit of top end flow off the high performance heads and made them look pretty mediocre As I recall that testing was done in a homemade flow bench at a shop in Southern California. You can converter flow depressions to 28” if they are take at 12”. But if those are flow numbers from the McCarthy’s efforts they still won’t be close to correct. IRC the conversion from 12 to 28 is a factory of 1.37.





My goal on this engine is to put everything back stock appearing, numbers matching and even casting number matching on everything. I would love to take it to a F.A.S.T. (Factory Appear Stock Tire) racing event someday. Not be competative, just to have fun. We have a 72 Plymouth Satelite built similarly to my T/A, it looks like it is a low compression completely stock 400 with a/c and factory manifolds, but it is a 542 CID inside, pushing 600 HP. Kind of built similar too a FAST build but also built to drive on the street…Headers are the only thing I am will to leave on my T/A that aren’t stock. But honestly I would love to even have the log manifolds back on the T/A. I have other engines 455s, 400s ect… I could have used in the car, and have other heads that out flow my 6x-4s. But, I wanted to stay as original as possible. Not many of my cars are original like this car, I am trying to keep it that way… And not make it the slowest muscle car I own.

More pics: My helper back when I brought the block for my T/A into the office to design the main girdle. I seem to have lots of pick, just no good ones of the outside of the car.

The Christmas photo of my boy in the sock hat with Smokey and the Bandit playing in the background with the top cut of the car..too funny. I have no idea what was going on that day.

[Murf]

Hey Jay sounds like a kewl thread! How many Firebirds you got anyway? Did you ever have time to see what was up with the heads on the one you had out at Great Bend?

I put A.C. on the wife’s car over the winter & some other small projects. I hope to get some miles on the Rhoads lifter setup & see how they work out.

Look forward to your posts!

Murf

[77 TRASHCAN]

I would have preferred a silver TA, but am glad for my black car. For whatever reasons, silver paint on GM. Cars back then, always had problems.
Did 77’s come with honeycomb’s? I’m guessing that’s how you ought it....

[Jay S]

Originally Posted by 77 TRASHCAN

I would have preferred a silver TA, but am glad for my black car. For whatever reasons, silver paint on GM. Cars back then, always had problems.
Did 77’s come with honeycomb’s? I’m guessing that’s how you ought it....

IRC, 76 was the last year for honey comb’s. I like swapping rims for different looks though, it will likely have an assortment of wheels on it. I am not sure what the car had when it was new, I am guessing it had 7” snow flakes. I suppose it could have had rally 2’s though. I wouldn’t mind some 17” snow flakes, but if I spend that much on new wheels it wouldn’t be as fun to do wheels swaps, the big snow flakes wouldn’t look quite as good on any of my other cars….

[Jay S]

Side by side shot of the stock factory intake port and the same intake port matched to a felpro 1233 gasket, versus stock. Hard to see the difference until you look closely at the metal left to seal it up. Plus another 455 out on the shop floor going in the t37.

I have the longer Dynomax 17748’s under the car. I had to remove them and flip them to make the flow master tail pipes work. Which also took some work using the longer casting mufflers. In progress.

And one of my helpers, every time I crawl under the car he becomes my best friend.

A photo of our first car. 71 Chevelle that has a 1970 455 Olds in it. One of the other many project going on at the same time as the T/A. Finally finished the fuel tank and drove it around last week. First time is many years. I added a sump so the engine doesn’t get starved at the track. It is in front of my T/A for paint and body work. It will be a little while before I tear into the paint on the T/A.

[Jay S]

I am finally getting caught up on my T/A project. I had it all ready to go to the Pontiac Uprising in Great Bend last weekend, then the night before about 9.30 in the evening I noticed a puddle of brake fluid at the back of the car. A brake line rusted out. I cut it back to where the line was covered with undercoating, got the flaring tool out and fixed it today.

It has the Stock 77 intake on it now. I filled and blocked off the driver side heat crossover. The passenger side is still plumbed into the intake, so the factory choke is still functional. I bought a electric choke from Cliff if I decide to plug the heat crossovers off completely, but so far I have not regretted leaving it as is. I put freeze plugs in the EGR. I was considering trying to keep the EGR, mostly because everything for the EGR appeared complete yet on the intake. It was more just for curiosity then anything, to see how the engine would respond. Then while plasma cutting a bigger hole for the Bulter valley tray PCV location mismatch, I burnt up the EFE/EGR valve on the front of the intake, I would still like to have it on there and non functionally hooked up just for nostalgia. Lol. Those aspirations quickly disappeared at that point when the valve was on fire. After that I went ahead and opened up the intake below the carb, there would be no EGR.

The epoxy I ordered months and months ago never came. I was going to fill the top of the intake ports to line the ceilings of the intake ports to the stock intake (I took them to far). But, I ended up changing directions on the heads. I had a pin leak on an exhaust port to repair. For some reason I bought bigger welding rod than I usually use, and I really messed up that exhaust port trying to fix it. I decide I really went to far on the exhuast port porting for a street engine, several areas are really thin on the exhaust ports, so I worked over another set of 6X-4 heads.

On the next set I contoured the short side turn sooner, and did not take near as much material off the roof, and port matched the intake manifold and head ports to a 1233 felpro gasket. Quite a bit shorter ports than I had on the other heads. I gained 18 cfm over the other heads on the intakes. The new heads flow 310 cfm @.7”, instead of 292 cfm @.6”. Plus I did it without any epoxy or welding anyplace. I did loose 12 cfm exhaust flow compared to the other heads.

I changed the valve springs so that I can try 1.8 rockers arms down the road to use more of the intake flow I found in the heads. I dropped the seat pressure some to 160 lbs and increased the spring rate to 413. I moved the valves from the other heads over to these. I did the oversized valves in my shop on one head, I had a friend do the other head. Both heads are milled, .008 and .010”, the compression is still just over 11:1.

Going into the porting the stock intake I was a little unsure how well it was going to go because the port exits are tiny. I was pleasantly surprised that after I port match it, the ports get much bigger in further. The port matching actually straightens the ports out and provides a straighter shot into the head. One port had a pretty big restriction that took some work at an intake bolt boss. Opened up the plenum is impressively deep. I think it is likely deeper than any of the other early intakes. I was very pleased with it, and it runs and sounds great. The choke was not functional with the t1 intake that was on it, it is good to have it’s street manors back. It idles at about 650 rpm, has a slight lope with the X pipe on the car now. The X pipe tamed the idle quite a bit.

I am getting close to being finished with mechanical projects on the car. I have Trans Am Racing wheel and 275/50-15 Nitto drag radials on the back of the car. I ordered a fender flare that was broke. I am down to tracking down the a fuel gauge short, dash light short, and finishing the tail pipes on the exhaust. One front caliper has a bad bleeder, and the A/C need some work, and the billet midplate needs to go on the tranny yet. Still plenty of stuff to do, just going to enjoy the car for awhile.

Next time i have it out I’ll get some picture up. It looks SOO much better with the vintage looking Trans Am wheels and the big tires on the back! The Keystones aluminum rims I had on it got moved to another car. I am hoping to take it to my local 1/8 mile track here in the next few weeks.

[Jay S]

Hi Murf. A/C in the convertible, that will be sweat. Your wife is going to want to drive that ALL the time!

This thread is for the same car I had at Great Bend. That first photo in post 1 is what I want to get the car back too.

I did some brazing on one of the intake ports and got in a hurry and didn’t take time to pressure check it. It was the only place I did any brazing in the head, I ended up removing all the brazing and redid it with a cast iron welding. The cast iron rod I use has a really high modulus of elasticity, higher that the factory iron, it is really resilient to cracking. I thought at the time that brazing would be a good fix, but where there is a thin area right next to a thick area it is tough to get the brazing to stick to the thicker iron. Brazing doesn’t mix well with other welding right next to it. I had to start over. I attached a photo of pressure checking.

I am switching back to the factory intake right now. The T/A is in the back of our race trailer. I have been looking and I have partial picture of my car. But no full photo’s. I think they were in my old phone . Lol

For Pontiacs we have a 68 GTO 400 HO with ported 16s (314 cfm) stroked to 455 cid, it is getting the Rhoads hyd roller cam set up we have. Our 71 T37 has a 455 and 280 cfm 96 heads, it is 10:1 and a big sff cam. The GTO is build similarly to my T/A, it is a high compression 11:1 pump gas build also. We are working on those, just went thi both engines. We also have a Super Stock 400 HO engine for the GTO we have been rounding up part for it. Not sure when we will get to play with that though, the GTO is going to be in street clothing most of the time. My brother and I just bought the GTO last year.

[Jay S]

I accidentally posted someone else’s engine photo last night, it was my reference photo.. Hard to tell on my phone. Here are some project photos. Plus the t37 out in the from of the shop going on at the same time.

[Jay S]

Ha! Murf that was suppose to be Sweet..not sweat. Sweat is what you had without the A/C!

First photo is of the main bearing oiling opened up.

Bottom Intake Port view, I think I had the 2.11s yet in that photo. That was around 275 cfm flow. 2.125” came later…


Bare short block weighted in at only 154 lbs!

And a random shot of one of our other past cars. I will through those in now and then so you don’t get to bored wandering thru this thread.

[Jay S]

That silver T/A in the first photo was a low milage survivor car I took photo’s of to help document what my car originally looked like. My car has been that dark grey ever since I had it. It had dark tinted glass, kind of a darker color theme to it with the black bird, stickers and dark tint. It probably looked mean back when it was fresh, but scraping the glue left over from the crappy job someone did on the tint was not fun at all!

[Jay S]

Is there anyway to delete that spam post?

[Murf]

Ha! Murf that was suppose to be Sweet..not sweat. Sweat is what you had without the A/C!

Could go either way. I haven’t got it working yet! ��

Sounds like you got a lot of irons in the fire!

Will be interesting to see what you can get out of that combo in “stealth mode”.

[78w72]

silver/red 77/78 t/a's are my favorite color combo for these later year cars, but im kind of biased since that was my first T/A back in high school & into my mid 20s, was a WS6 W72 T top car with no power options.

sounds like a nice build, couple of questions on the specs posted- 11:1 with iron heads on pump gas? that seems rather high, does the cam & tuning combo allow you to do that without pushing the limits of major detonation? & is this the original 557 block that is stroked & plans to go mid 11's? isnt that way past the "safe" power limits of these thinner blocks based on what ive read over the years.