I recently converted my 1965 289 from 2v to 4v. I replaced the original intake manifold with a '66 4v. I replace all the lifters with new original types, so a valve adjustment was required. I am using a new Edelbrock 500 cfm carb. It started without issue, runs good at higher rpm's, but runs rough and the motor shakes from side to side at lower rpm's. When timing the motor, per the shop manual, I unpluged the vacuum hose from the distributor and set to 6 degrees btdc. When I plug the hose back in, the idle rpm's shoot way up and the carb idle adj screw is at it's lowest setting. So basically the two things I changed was the carb, and valve adjustment. It was running fine prior to starting this project, but had a sticky lifter due to sitting in the PO's garage. Any ideas as to what I'm missing here?

Thanks, Tim

 

was the carb new or used?

 

Brand new

 

could be a vacuum leak. mine did that after my swap. you end up reducing a couple vacuum lines. have you double checked those? Fuel can be setup to rich as well.

 

plug the hose into the port without vacuume at idle.theres 2 on the front one is to dizzy other is vacuume all the time.recheck the lifters make sure one isnt going down new lifters on an old cam?did you lube them?and recheck firing order