Help... BBC piston ????
 

Does anybody know what the replacement piston is for a 1970 454 360 @ 415 hp. Its not listed in NHRA's list. Or is this a super stock only combo. Classification guide doesnt tell if its ST or SS.

Factored HP seems a little high too. + 55 HP. Whats the big deal. Small valve, oval port, hyd. cam.

Does anybody run this combo in a 70 chevelle.

Thanks
John Beasaw III
1096 F/CM 70 chevelle

Maybe not too many running it currently but I know somewhere in my piles of car magazines I have an article detailing that combo in a '71 Chevelle. The article was probably back in the mid 80's. I am pretty sure that it was a flat top motor and they were using cast slugs !

According to the blueprint guide, it has a 12cc dome with a 96.4 cc chamber, for 10.25:1 compression. Yes, 415HP is the factored HP for STOCK.

There is no piston listed in the guide. But I can look for a 12cc closed chamber dome piston in my older catalogs. You'd just about have to have some sort of original sample to get a new set made and approved.

I'd say it's a tough combination to make run. That's an oval port closed chamber engine, with only decent compression, and small intake and exhaust valves, but it's factored about the same as a high compression rectangle port 402 with BIG valves. It's a low RPM combination, all torque.

Alan Roehrich


Bring "AA" classes to NHRA Stock Eliminator!

The closest thing I can find to the correct piston is the Speed Pro L2399F. With a 2.07 intake valve, and under 0.480 lift on both valves, I'd say the HP factor is high, especially since I'm not sure how good the intake manifold is. At 415HP, I'm betting it'll be hard to run a decent number.

Alan Roehrich


Bring "AA" classes to NHRA Stock Eliminator!

Is this not the same piston I run in mt 71 454/425 B/SA Chevelle? It got an .095 dome and is closed chamber. Bruce C.

Bruce, I think it is, according to the blueprint spec sheet (it matches up really close), but NHRA just does not show the 360HP engine on the piston list. I'd say a call to Glendora is in order.

Alan Roehrich


Bring "AA" classes to NHRA Stock Eliminator!

Alan , I run a closed chamber piston (095 dome)with a open chamber head. As for the 454/360 combo , the only problems I see with it is the terrible (submarine) intake, and the horse power. Bruce

Bruce, I agree completely. The intake is a real power killer, and when you combine the intake with the small valves and low lift cam, I just don't think it can compete with a 402-375 that carries about the same NHRA rated HP.

Good luck selling your Chevelle. There was a nice LS-6 at Bowling Green this weekend, it's Kevin Wells' red 70 Chevelle and he was pretty damned quick. About as quick as our 427 Camaro and Arnett's 396 Camaro, and maybe quicker.

Alan Roehrich


Bring "AA" classes to NHRA Stock Eliminator!

Guys thanks for the input. I might just scrap the idea all together and keep with my crate motor stuff. Maybe a 502/502.

Thanks Again
John Beasaw III
F/CM 1096