*NEW UPDATED* W72 Build Plans, Getting Stroked
 

Good Evening everyone, as many of you are aware of from my other W72 build thread, we are getting ready to build yet another Pontiac 400, this time a 1979 PWH W72 400 out of a Trans Am. The original plan in my other thread was to upgrade the 400 as much as possible while retaining the numbers matching parts on the outside, but after calculating the cost of good pistons, better 5140 rods, and having the crank turned and everything balanced, it comes within a few hundred dollars of just buying the Butler Performance Balanced Stoker rotating assembly ready to install, after I get the block decked and bored, and the end result is much better parts for the money, a bigger 467 c.i. engine, while retaining the numbers matching look to the eye. At this time there will be no head porting in the budget, just a nice rebuild and valve job on the 6x4 heads, upgraded with Ferrea stainless valves, Crower 68404 springs set up at 1.570" Installed Height, and 7/16" studs and poly locks. This engine should come out somewhere between 9.6 to 9.8- 1 compression. We are now thinking we will use the Lunati VooDoo 704 camshaft in this. Here is how the build plan looks now

1979 PWH 400 XX block
Bore- 4.181"
Zero Decked
Butler Performance Rotating Assembly
Eagle 4.250" crank
Eagle 6.800" H-Beam rod
Ross/Butler 8cc Flat Top 2VR piston
Total Seal Plasma Moly rings
Melling M54DS pump
Stock (non ported) 6X4 heads, 7/16" Studs and Polylocks, Ferrea Valves
Felpro 1016 .039" head gasket
Quench .039"
Compression- 9.6 to 9.8-1
Lunati VooDoo 704 Camshaft
276/281 Advertised Duration
233/241@.050
.504"/.527" lift
110° Lobe Seperation
Thinking of Installing it at 104° I.C. according to the advice of Harold Brookshire and Paul Carter
Crower Camsaver lifters
Crower 68404 Valve Spring installed at 1.570"
Cloyes 3512X9 billet timing set
Stock 1.5 rockers
Stock Cast Iron intake
Qjet Recalibrated with Cliff Ruggles parts
Recurved HEI distributor
1 3/4" headers, dual 2.5" exhaust
Super T10 4-Speed Manual transmission
3.23 rear gears

This is 100% street car on pump gas in an original 1979 Trans Am. What do you'll think about the new stroker plans? I know head porting would be even better for the bigger engine, but it is not in the budget at this time. Sound like a good plan?

Thanks

To help that late production block live with that .060” overbore you going to want to do a half fill on that block!

Build looks good, hopefully it's a later 4 speed block. I'd opt for the forged crank option. I've seen just enough of the Eagle cast cranks break to avoid them, if nothing else you'll sleep better at night. Never tried one of those cams but I have had Lunati grind several custom cams for us on wider LSA's with excellent results. Most recently they did a cam for us for a 425 Olds build, then another for an Olds 455. Both were in the 230-240 @ .050" range moved out on a 113LSA. Good idle, throttle response, street manners and no issues whatsoever on pump gas with mid 10's for compression........Cliff

That's our recommended build for the 78 and 79 400's. We build a lot of them. You can save money by using a cast crank, cheaper forged rods and put that money towards some head work and pick up extra power.

You will need to swap out the flywheel because the aftermarket cranks use the 2.75 hub

its an XX W72 block, cast from the early 481988 blocks. no need to fill it for a street car.

Thanks Cliff, the block is the original 1979 4-speed XX block 481988

Fantastic! Thanks Paul. Yeah, we had already thought about the flywheel as well

Yep, its the original 481988 PWH XX block

The extra stroke will get the CR better also. If you are going Ferrera valves I'd still go longer so you have a better IH.

Thank Skip, but unfortunately we already have the Crower 68404 springs, so we will have to make do Lol. It will always retain the stock 1.5 rocker though.

That is what the "For Sale" section is for:)

Paul, what HFT camshafts do you usually use in this type of build? I know Cliff likes the 60919, Paul Carter likes the Voodoo 704 in the bigger engines, and all that I have seen on both Crower and Voodoo have been excellent results, but we haven't tried the Voodoo before, so we wanted to give the 704 a try this time around. Harolds lobe design and offset of the lobe in relation to the centerline of the cam core on the Voodoo cams seem like they work extremely well, even with their 110° Lobe Seperation. We have used the Crowers in the past with great results. Just curious what you use in his type of application.

Thats a great point! 😂

Interesting build, what horsepower are you shooting for/expecting? How come you're not keeping manifolds vs headers while retaining numbers matching parts throughout?

Thanks, the car already had headers on it, and exhaust would have to be redone in order to run a set RA manifolds

Evaulate what the pressure will be with the Crower 68404 valve springs at your VERIFIED installed height. With that in mind take notice that based upon his dyno testing and extensive use of Voodoo cams Paul Carter recommends 130-135 lbs seat pressure with 30 degree seats and 330-340 lbs open pressure with the Voodoo hyd flat tappet lobes. Less pressure ok with 45 degree seats, still shoot for 110-115 at least for the Voodoo 702 & 703.

Also he suggests to keep the distance from coil bind around or under 0.100". Also keep in mind valvesprings will lose pressure after run in.


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90% of our cams are custom and Nitrated these days. Crower has less modern designed lobes that seem to work well with Pontiacs 30° seat. The Vodoo cams help build cylinder pressure by design. I think it is cool that you are using header on the build. They will favor a slightly tighter LSA.

I love PY, So much knowledge in these pages.

GT.

I agree! By far, the absolute best Pontiac forum there is. I can read about camshaft and engine information for days straight here in the Street section Lol

That's a pretty choppy cam if ground on a 110 LSA. Not saying it won't work, at all, but be prepared for a pretty rough idle.