my 289 idles fine and runs fine at speed in neutral but when i put it in gear it stumbles all over the place. Is this a vaccum problem or could it be something else?
Stumbling in gear can be a few different things.. could be spark, check while running, in gear after dark with the hood open. One person in car holding break and applying a little gas, the other looking under the hood for jumping sparks. If not, then check your vacumn hoses and fittings. You can spray carb cleaner around questionable hoses and fittings. If neither of these is the culprit, then I would look to the carb.
I replaced the vaccum hoses and caps on the front of the carb and the modular trans line is new. I dont know where a vac leak could be comming from. The intake has been on for over 2 years so I know its not the intake gasket.