need help 67 396 chevelle poor mileage also backfires on start up holly carb edelbrock manifold

I would start by checking your timing, also check to make sure the spark plug wires are in the correct order! Also it's Holley. But if it runs poor, and back fires, it's more than likely a timing issue. There is a ton of information in the engine, and performance forums, use the search function button at the top of the page using backfire as a key word, you will have plenty to read.


Rocky

thanks Rocky right on the money the timing was way off and the car ran great so well in fact after the first run bent a push rod. Back to the shop .