CamMan83

Just last weekend I did a motor swap in my 86 IROC. I changed out the TPI motor and put in my Supercharged 350 from my other Camaro. Before we did the swap the motor ran strong and everything was sound. Now when I get on the motor it backfires through the carb and about 5 seconds after i shut it off it sounds like an explosion in the exhaust system. Could that be an air leak at the carb or supercharger? And the tach acts up when I am getting on the motor, the connections are good but could the a bad coil or module cause that problem. Please help, this is driving me crazy!!