It stumbles under hard acceleration. The spring tension, should it be increased or decreased?
Yes I installed a new engine to ground wire. I don't remember a brace on the starter when I bought the vehicle.
you have to adjust the spring tension on the air door and/or the the rate of extension of the choke pulloff that is normally connected to the door linkage
I have a Haynes manual on rebuilding quadrajets but it doesn't contain tuning information. Can you suggest a book that does?
if it is a timing problem would that normally be too far advanced or retarded?
One last question. I noticed when I rebuilt the engine the vacum measured at the intake manifold increased to 25 inches while at idle (about 1000 rpm). Can this be part of the problem?