I took a step back and started over on troubleshooting. Vacuum is down and I think I traced the leak to those scary asbestos looking gaskets between the intake and exhaust manifolds. One is crumbling on a corner and it chips away easily. My revs were increasing when spraying carb cleaner in that area.
I took off the carbs and tried to reach those 4 nuts but they impossible. I then loosened the intake/exhaust manifold and exhaust bolts but one of the studs is unscrewing from the engine and coolant is coming out of the hole. Is the stud really holding back coolant under the intake mounting bolts?
Oh well, looks like I need to put my driving plans on hold and rip this thing apart.