[vertigto]

So...the original 400 rebuild for my 70 GTO is finally done and looking to get some perspective from the Pontiac faithful regarding the results. The engine was broken in on a dyno and made a couple runs. Not yet installed in the car.

Here are the basic specs (ask if you want more). Any guesses on the hp/torque??

- Stock YS bored .30 over (ICON/Scat H-beam/forged)
- Stock crankshaft
- Ultradyne cam (221/230 @ 0.50, 454 lift, 112LSA)
- Stock #13 heads (with a little cleanup/3 angle valve job (Ferrea) and 1.52 roller rockers [asked for stamped OE or roller-tip])
- Stock intake
- Stock Qjet
- @ 9.5:1 - 9.75:1 compression (need to verify exactly)
- DUI ignition

[steve25]

385 hp.

[Mike Davis]

376HP

[grandam1979]

360

[SD455DJ]

Log exhaust manifolds, ram air manifolds, or headers on the dyno? If either of the manifolds, what head pipe did you use?

Dennis

[vertigto]

FWIW...confirmed 9.54:1 compression.

Headers on the dyno. Will have oversized RARE manifolds/downpipe and 2.5" exhaust/Flowmasters when installed.

[SD455DJ]

Originally Posted by vertigto

FWIW...confirmed 9.54:1 compression.

Headers on the dyno. Will have oversized RA manifolds when installed.

I'll say 390 hp/445 ftlbs torque corrected.

Dennis

[vertigto]

Will give some more time for others to guess before revealing the results.

I will say that there were only minor tweaks in-between 3 runs that produced @ 5 hp /3 ft. lbs trq gain. I think there might be a little more in it with some additional tuning.

[Will]

Everyone else so far is thinking along the same lines. I'm going to say around 380 horses and ~ 425 - 450 ft-lbs

[SD455DJ]

Originally Posted by vertigto

Will give some more time for others to guess before revealing the results. I will say that there were only minor tweaks in-between 3 runs that produced @ 5 hp /3 ft. lbs trq gain.

Vertigto, The suspense is going to kill us!

Dennis

[tom s]

You made a "couple"runs?No results on them?Tom

[vertigto]

Okay...I'll cave.

Last run was 403/482. Previous run was 398/480.

We (builder and I) were shooting for 400hp with a solid/durable foundation. Thoughts??

[steve25]

Please give the RPMs for these test and the more meaningful average numbers if you have them?

[vertigto]

I only have a low resolution/grainy video on my cell phone right now for the second to last run. Looks like 398.64 @ 5000 and 480.52 @ 3600. The builder is going to give the cam card/dyno sheets to the restoration shop when the engine is picked up. When I get a copy, I'll post them up.

[grandam1979]

Wow that’s great for a stocker I was off by 43hp it will loose some when you put the manifolds on it still nice for pump gas.

[vertigto]

Originally Posted by grandam1979

Wow that’s great for a stocker I was off by 43hp it will loose some when you put the manifolds on it still nice for pump gas.

Yep...hoping the loss is relatively minimal with the oversized RAREs and 2.5" H/40 series Flowmasters. Didn't want the headaches with headers, for what most threads characterize as small gains.

[SD455DJ]

Originally Posted by grandam1979

Wow that’s great for a stocker I was off by 43hp it will loose some when you put the manifolds on it still nice for pump gas.

Agreed. You'll be in the 380 hp/460 lbft area with the RA manifolds, which is still getting with the program...and with decent gears (3.23's or lower) you'll be in the low 13's/high 12's easy with good traction and a great exhaust system.

Dennis

[vertigto]

3.23s with Auburn Pro limited slip...

[OCMDGTO]

Very nice build, greatly exceeded my expectations. You taking it to the track?

[Will]

Fantastic, and congrats! Those are some nice numbers.

I was only off by ~20hp but I greatly underestimated the torque. WTH is wrong with me, it's a PONTIAC after all... LOL.