I just placed a new 383 stroker in my 96 camaro, I changed block to a 4 bolt main from a 95 corvette. Sometimes my car wants to back fire when I'm on the highway and sometimes it runs perfect. but when it starts to back fire I hit the throtle and it responds pretty good. I have the original injectors, could that be the problem? I already changed the opti spark, but I havent programmed the cpu. could that be the main problem? I havent programed the cpu because I was waiting to have everything ready like some better heads, torque conv. etc. basically I just have the 383 block w/lt 4 hot cam kit and headers. stock heads,

A bored block and stock heads scares me that has so many potental problems of complete engine destruction.

The thing with the backfire may very well be the computer trying to correct the duty cycle or pressure of the injectors.

I personally would not continue driving this car until you get the computer tuned and heads that match the block

I have a 96 LT1 in my 67. I find a lot of helpful advice and info on this site, just go to the LT1 section...

http://www.ls1tech.com

Good luck, and personally I would start out with matching heads, maybe a little bt heavier injectors and a PCM tune.

Adam