How do you adj air fuel mix on a old rodchester 4jet not quadjet

Question

it is in a 1958 Chevy it is pre quadrajet called a 4jet or 4bc just rebuilt it all new gaskets float is dead on all jets are clean but blows black smoke out tail pipes i know it is running too rich p;ease help a new one is two expensive

Answer 1

There is no jet adj only idle> Check the timing or advance it a little and see if that helps> Check the vacuum advance>If still smokes might have to re jet down in size>

Answer 2

run each jet in until they seat, not too tight or you will break the seat, now back each 1 out about 1/4 turn, start your car and make sure the choke is off and turn each 1 out about 1/4 turn until you get a smooth idle.

Answer 3

powervalve not sealing, this is the prerunner to the qj of the 70s