1950 DeSoto stalls in traffic jams

I had a 953 6 cyl flat head engine, with mechanical valve lifters, car that would die as I was slowing down at a stop light or on a highway ramp. It would start easily when cold but was very hard to restart after it warmed up. Sometimes it took 30 minutes to restart. The problem didn't happen till it was running at normal temperature. My temporary fix was to use the hand throttle to increase the idle to 1,200 RPM. Eventually it became apparent that it lost so much power it had difficulty on steep hills.

I did a compression check on the engine both cold and hot. Two cylinders had a significant drop in compression when the engine was hot. I had a a shop do a cylinder draw down check and 2 exhaust valves were not closing completely when hot. All the valves were readjusted and the engine stopped dying and the power on hills returned. Apparently, when the engine heated up, the valve stem increased in length causing the problem.

This drove me nuts because I was thinking it was a carburetor or gas flow problem.

I didn't recognize the fix, it was an 85 year old former mechanic who suggested checking the valves.

I don't know if the valves are your problem but you might check them.

I've been abroad and now I'm back I am really hesitating but have to go on, it won't fix itself...

Anyway, I've been trying to remove the inner fender to get to the valve but cannot get it out. How do I go about? All screws are out.

I had to remove a lot of rust inhibitor (tarry stuff) but still the panel is very snugly fit on the front end.