Back flush the radiator, check the fanbelt for proper tension, and make sure the packing nut is not leaking (drawing air) Make sure the manifolds are not leaking. Also the ignition could be set too retarded or carb set too lean.

@chevy4life-2 Overheating or overflowing? They are not necessarily the same. If these non pressurized systems are over filled, when it gets to operating temperature and the coolant expands, it has to go somewhere and exits via the overflow. This is a fairly common issue.

I went through this with my 1936 Standard. Not only should you flush the radiator but also the block. Remove both radiator hoses and the petcock on the block located on the lower driver side of the engine. Use a hose to flush out the block. Hopefully the water passages in the head are not completely clogged with rust particles. If it is, removing the head is required to clean them out. I even used a coat hanger wire to poke into the block to free up rust particles once the block petcock was removed. Something else to consider is the engine timing. If it is off, it can cause heating issues.

@j-franklin 

Hi, everything you .mentioned looks fine but the carb.  It seems to be idling high there was also a fuel leak in the line that I fixed. I may have to have the carb rebuilt. 

@david-zamecnik 

Thank you for your reply.  I did flush the radiator but have not done the block I will try that next.  I did have the head redone so that is like new. Also it is idling high after I started it, I had to push the throttle down so it wouldn't idle high. So I am guessing I need to have it rebuilt. 

Thanks again for your knowledge. 

Something else to think about. When my coolant level inside the radiator drops below the fins inside the radiator, the radiator fluid will come out of the overflow. When I add fluid it stops. 

My '35 had a similar overheating issue.  After several flushings it still overheated.  Solution?  I pulled the engine, removed the head, removed the freeze/core plugs, and jetted the water passages with a pressure washer.  There was an unbelievable amount of sludge and rust in the block.  The engine sits at a slight tilt toward the firewall and rust accumulates there.  Just running a garden hose thru that will not break up the dam.  Yes, it's extreme but it worked great and always runs cool, even during parades and low speed driving.