I would imagine that your tranny is old enough to have a modulator valve. That needs to be hooked up to the vacuum line at all times. I don't know if it has an affect at idle but it wouldn't hurt to check it out.


1951 GMC 1 Ton Flatbed -- It is finally on the road and what a great time I have driving it!
1951 1 Ton Completed


My Chevy Master 4 Door is on the Road!