I have a '60 Corvette that sat for about 3 years. The car had started and ran without issue before going into storage. After replacing the coil, condenser, starter and battery I'm having a problem having it start and run consistently. It will start and run fine once and 10 minutes later crank and crank and backfire thru the carburetors and not start. The car has a 283 with 2, 4 barrels and a 4 speed. The fuels tank and fuel lines have been replaced. I'm just frustrated beyond belief Thanks