[Adger Smith]

Joe,
Yes on Manifolds.
From NHRA Specs:
24 - Al Manifold 25 - Alt manifold - 3967474,3933163,19131359
Intake Manifold 3933163 with an open plenum (divider cut down) is acceptable as of June 6,2002

I think a couple of years ago, I haven't done it lately, but if you run the actual numbers the compression comes up a little more on the 402.
As for HP See below:

CHEVROLET II - 1970
Cont

402 402 402 402 402
* ** * * **
AUTO STICK
A A A
350 350 375 375 375

9.67 9.26 8.67 8.56
9.84 9.43 8.65 8.65


340 355 395 390 395
7.31.02 7.31.02 7.10.07 2.21.06
405 400 405
7.10.07
Sorry it didn't copy and past very neatly
I also think there might be an advantage in carb /hood clearance over the 70 mod camaro.