Popping out Exhaust

[DC AUTOMOTIVE]

Truck is a 1985 C2500 with a 350 engine.  Odometer says 68000.  Recently rebuilt the carburetor.  The truck runs great except that if you go 3/4 to full throttle, and then let off the gas quickly, it pops out the exhaust.  Sometimes 1 pop.  Sometimes multiple pops.  We are just starting to get into carburetors, so we know the basics.  Any help would be greatly appreciated.

Thanks

[Cliff Ruggles]

What kit did you use?

[DC AUTOMOTIVE]

It was a Walker kit from O'reilly's  #151038A

[Cliff Ruggles]

Those kits are bottom of the barrel.  The hole in the fuel inlet seat is too small.  The seal on the pump is garbage and you didn't get a secondary cam/spring in the kit or a retainer for the power piston.

If you are experiencing problems at heavy/WOT the problem could be a number of things.  I'd start here:

https://cliffshighperformance.com/product/quadrajet-rebuild-kit-sr

This is a complete kit and will get the carb up to par in every area plus lifetime warranty on the N/S assembly and accl  pump......