Hi Folks
I am new to the forum but not wrenching. I have a friend with a "72" chevy truck with a built 350. I dont know the actual build but what I can see is this. Holley 750DB w/ hiperf electric pump on a Edellbrock dual plain manifold, headers, camel hump heads, Mallory HEI and a roller cam of unknown specs.
The engine runs great and has no problems of the line under full or partial throttle. The problem is it backfires when it gets to higher RPM. If you are cruising on the freeway at 60 and punch it it does fine for a few seconds than starts to backfire. The timing is about 8 BTDC and a total of 38 BTDC the plugs look good at idle and full power. I have checked all the basics and cant find any obvious problems. He brought the truck to me in frustration as three other shops could not fix the problem. The only real build problem I see is that the carb CFM seams a little big to me. Any ideas?
I am new to the forum but not wrenching. I have a friend with a "72" chevy truck with a built 350. I dont know the actual build but what I can see is this. Holley 750DB w/ hiperf electric pump on a Edellbrock dual plain manifold, headers, camel hump heads, Mallory HEI and a roller cam of unknown specs.
The engine runs great and has no problems of the line under full or partial throttle. The problem is it backfires when it gets to higher RPM. If you are cruising on the freeway at 60 and punch it it does fine for a few seconds than starts to backfire. The timing is about 8 BTDC and a total of 38 BTDC the plugs look good at idle and full power. I have checked all the basics and cant find any obvious problems. He brought the truck to me in frustration as three other shops could not fix the problem. The only real build problem I see is that the carb CFM seams a little big to me. Any ideas?