I have a 1970 Camaro. I have put a 350 in it 4 years ago. It came from a junkyard and was out of a 75 camaro. It has a 2 bbl..been working great for past 4 years now. It has a stock HEI distributor. I recently put 202 fuelie heads on it.I now have a backfiring problem. I have a 1 year old battery and plugs(clean).Brand new wires. New starter and alt. The timing is set at 8 before hooking up the vacuum advanced. It is a stock cam.Not a old or stale gas issue.I have been driving it regularly for the past 4 years,has fresh gas. Any other questions on it,please ask...I just want to know what could be causing the backfire.

 

Well...to help those who may read this thread...Even before getting any suggestions or responses...The problem was diagnosed as a cracked spark plug.

I feel really stupid for not being more observant..i just assumed that because they were only a year old plugs,they were fine...live and learn.

Glad to say I have replaced the heads on my camaro and he is now running great!!! Better than ever even!!! Time to show him off at carshows...and will definitely be sharing his carshow pics!! Still glad I joined this forum..I love seeing other Camaros,and hope to help and get help in the future!!