Hi all.
I have a Idle issue that I can't seem to sort out. I have great starting and idling when in neutral and park (tach will read about 550/600) but once in reverse or drive with foot on the brake I get a vibration (tach will read about 475/500)...I had the carb redone last year, brought it back to him yesterday just to open it up and go through it (all looked good). Also install a new fuel/vacuum pump last year. I've rebuilt the brake booster (I know there a small vacuum hose in there too) I've checked the vacuum (running about 21" @ the manifold. I have a tee on the hardline). Do I need to check each vacuum line for a leak.

Could it be a timing issue? I've read timing lights are pointless on these motors. Maybe rotate the distributor a bit? I'm just spit balling here.

Thanks all