Wally

It sounds like the engine was tuned before it got to full operating temperature. When the engine gets fully warmed, many items expand and when this happens, things run differently.

Perform all the tune-up tasks, just get the engine good and warm first.

SWEET
Sergeant At Arms: Old Dominion Stovebolt Society
BUNS?!?!?!Where we're going, we don't need no buns.....
1950 GMC 450
1951 Chevy 1/2-Ton
The GreenMachine
In the Stovebolt Gallery