Banging out big block
 

I have a 482 big block that I ran 2 nights last season with my sons holley 1050 carb on it. It ran great. I ordered a new carb that was set up for my engine and it would launch great but would bang out shortly after it launched. We tried bigger jets and several trys with no success. The next week we put his carb back on and it started banging out again. Nothing else changed from last season. We checked plugs, valve settings, timing and a different coil. Nothing was found to be bad. Any ideas?

Did you check fuel. Pressure, volume, ect.

Yes, we pulled fuel line and ran pump into a fuel jug untill fuel cell was empty. It ran a full stream the whole time.

Ohm he plug wires, and maybe check the cap and rotor. Seen a rotor crack this weekend, causing a issue like your having.

carb
 

have you tried a tube from front vent to rear with notch cut at top

We have not tried the vent tube-but will. Also, I'll take cap off and inspect for cracks. Thanks guys

There is something that i have seen before is rpm and retard chips that go bad.

I'll try different chips if dist cap looks good. Thanks

I found out I have at least 2 broke valve springs. Some check to be a little weak. Thanks for all the help.