Well, I got my pipes on my blazer and rebuilt my carb. I have got all my vac lines hooked up, but it is backfiring through the carb when you accelerate it hard, if you inch the throttle open then it does not do it. I am open to any suggestion as to where to start looking for the problem. I am still in the erly stages of getting this engine running correct, but would like to fix this problem fixed first. Oh, BTW I am running a stock 4bbl Q-jet from a '74 burb on a stock intake.