Ol' Fart's Firebird Fantasy

[oldskool]

Originally Posted by Mark Yacavone

1 Yes, you can float the pins

2 Yes NHRA approved number

3 Don't argue about it, and don't use a lighter pin than you have to.

4. You can use a .980 pin or LARGER if rod is approved.

OK, so the optimum set-up would be to use a rod / piston / pin / ring combo which would just barely meet the NHRA min weight--is that correct ?

So, for this 350hp 400, that total weight would be 1458 g.

http://www.classracerinfo.com/Engine...px?ENGINE=2048

But I noticed some more specs on this page I need to ask about.

(1) The comp dist is listed as 1.695. But one of the approved pistons has a comp dist of 1.714. So, does that mean that you can use any comp distance you choose, which will optimize your combo with one of the approved length rods, and the max allowed stroke ?

http://www.summitracing.com/parts/sl...w/make/pontiac

(2) Wouldn't there be an advantage to running one of the BBC rods, because of the smaller big end and larger selection of cheaper pins ? The rod journals and bearings will be smaller, and lighter, with less bearing surface. All this will make the rotating assembly lighter, and should rev a bit quicker. Nothing major. But every little bit helps.

(3) That was for the optimum set-up. But it is also the most expensive. So, that brings up my final piston / rod question. Since the SP(TRW) pistons are MUCH cheaper than the other approved forged pistons, is it possible for a low buck guy to use the cheaper pistons and 6.625 Pontiac rods, and build a shortblock that can run slightly under ? Or to ask it another way, aprox how much quicker would the high dollar shortblock run than the low budget one I described ?