Carb cleaner isn't that good of a fuel, could be why it slowed down. If you have the over rich mixture problem solved, get it out on the highway and run hard for a while to really clean up the plugs and cylinders. If it doesn't idle better, change out the plugs. Fouled plugs don't always clean them self up.
As far as the vacuum leak, pull the carb off so you can see it up close and make sure the vacuum line fitting is sealed where it screws into the body. While it's off, look it over, tighten the screws, and make sure you have plenty of room at the spacer where you opened up the air holes. Also, make sure the intake manifold is clean where the spacer and carb bolt on, no rust or gasket bits. Use a straight edge across the base of the carburetor, after this many years, it's not uncommon to have bent mounting flanges. A solid flat surface with some 320 paper will flatten it back out if needed, but go slow. Over time gaskets compress and need tightened, and rebuilders are not known for using quality materials or the correct parts.
Those heat plates or spacer only use one gasket on the bottom, the carburetor sets right on it. Rotate it, flip it, what ever it takes for the slots and hole to align, or as you have done, make a new hole. They never will run right if the alignment isn't right, and while you are checking, make sure the spacer is flat.
Last edited by Joe H; 10/19/2025 1:14 PM.
