JLCustomizing

Had my quadrajet rebuilt and the shop said its still running a lean. It gets up and goes great but if you hit WOT it tends to bog a little bit and doesnt want to go as easy. I have .076 jets in it right now, the shop said I should consider going up to either a .079 or a .082. First off is that to big of a jump and second would I need to change my primary metering rods if I jumped up jet sizes? I have Cliffs kit on my carb but he only sells up to .077 on his jets.

five7kid

iTrader: (14)

You need to tune the secondaries, not the primaries. Only the primaries have jets.

The secondary rods & hangers, and the air valve opening rate are where you need to concentrate. A bog means the air valves are opening too quickly, which causes a lean condition.

The choke pull-off and air valve spring tension are the first two things you need to address. The choke pull-off can be checked with a vacuum pump - the usual failure mode is failure to hold vacuum. It can look like it's functioning when the engine is running because the engine supplies a steady vacuum. But, a leak in the diaphragm can allow the pull-off to release too quickly.