[bignate]

I've decided to pull my '80 Firebird back out and start working on it. The idea is to get into racing with it, and get some experience behind the wheel at a track. I'm going to build a 455 for it.

I have a set of #12 heads from my RAIII motor, a set of #670 heads, and a set of #061 heads. They're all in similar condition, needing about the same amount of work. Whatever ones I use will get new stainless valves, replace guides, a performance valve job, and resurfaced. I am not going to port them, however they will be port matched to the intake I use, which will probably end up being a factory iron intake.

My question is: Which of these heads would you chose for a flat top 455? I know stock all these heads will put compression over 12:1, but I'm not worried about that. It's not going to be driven on the street much at all.

Thanks, Nate

[BILL BOWMAN1]

670 would be my choice.

[ponyakr]

If you don't mind buying race gas, I'd use the #12's. We ran 16, 48, 62, 64, & even a set of RA4 heads on our 455 bracket engines. Ran RA4 clone cams/Rhoads lifters in most. This combo will idle smooth, work with stock converter, and make power to 5000. Won lots of races with this set-up.

My current bracket engine has 6x-8 heads. So, I can probably get by with 93 octane pump gas. Personally, I wouldn't waste a set of #12 heads on a bracket car. The 6x-8 cores are still cheap.

Don't know how quick you wanna go. We ran mid to high 12's in most. With more cam & gear, ran 9.85 on 1000' track and 11.82 on 1/4 mile track. Easy to go quicker with more stall and rear gear.

BUT, bracket racing is won with good reaction times, and consistent ET's--NOT quicker ET's. So, build it to be competitive in the bracket you'll be running. At our local track, I don't think they have a max ET for the quick bracket. They just have the electronics class, and the footbrake class, which they call "No E".

Check out your track rules. If you can run the bracket you want, with a 12 sec car, that's where I'd start. The less stall and rear gear you run, the less traction you'll need to hook it up. I always set ours up to leave from an idle, with a stock converter. There's no slip, so the car moves instantly, when you hit the pedal. This makes consistently good RT's possible, leaving on the bottom yellow. Takes a little more skill to jack it up on the converter exactly the right amount. Hey, this was our experience. Maybe some of it will work for you. Good luck with your racing !