The timing is probably retarded to be able to use the modern gasoline without pinging. So it’s about what I would expect to see. Your engine was designed to run on 90 octane leaded regular gas that was available anywhere 50 + years ago.
It’s a double-edged sword. Running late ignition timing means less power, less heat in the combustion chamber. However, because more fuel is still burning as it leaves the chamber, it also soots up and makes your exhaust valve hotter. The hotter exhaust manifolds will make your underhood temps soar.
Over time, enough carbon buildup on the exhaust valve will prevent it from sealing, and it will usually create flame jets that will damage the valve and head.
If you run your timing too advanced, that creates more immediate problems, as you will experience ping, detonation, and engine overheating issues. Under full throttle, that can break things and melt pistons, which is obviously less than ideal too.
Get your timing just right, and make sure your ignition curve is spot on for best results. =)
Your engine idle speed seems to high to me, hard to tell.
You need to put on a rpm counter so you know engine speed is correct before you start diagnosing. If your engine is running high, the butterflies are open more and less vacuum on gauge. It will give you a false reading.
I can’t tell where you are running vacuum gage from? Have you got it running off the carburettor? It should be run off the manifold.
I notice that you have heater hose running off the thermostat housing on the radiator side. Not correct, (as set up, heater will only work after thermostat opens). That is where the Distributor vacuum control valve goes, if it had one. Ideally it should have one.
If the engine had a Distributor vacuum control valve, one vacuum hose should go to the manifold, one to the ported port on the carburettor, and one to the distributor vacuum advance.
Bottom line, I foresee a few problems and you need to go back to the basics and get you intial timing correct for the correct idle speed with the correct (leanest) idle mixture, before you start to diagnose engine problems. Make sure you vacuum advance is plugged when setting timing mark with timing light, don’t guess.