1968 Pontiac GTO 400 Engine Back Fire Out Tailpipe On Deceleration
I have a 68 GTO with a 1970 Pontiac 400 engine. I installed a new manifold on Holly 770 carburetor this winter. I have noticed that when driving at higher speeds >50mph and take my foot off the accelerator the car will backfire through the exhaust. I have read that it could be a multiply of causes and that timing could be one of them. What is your opinion on what it could be and the checks I can do to nail down the problem.