Stuck rear drums on 33 Vicky

[KeithH]

New member here. I'm trying to get my late father-in-law's '33 back on the road.
It has sat for a long time in his garage. I've done the fuel tank, lines, and fuel pump.
She runs like a top, BUT stopping is another story. He has converted it to hydraulic
brakes some time in the past, but I'm not sure what they are from. There are 5 screws
between the studs. Could this be a separate drum/hub combo? I'm to the point of
trying to remove it, that it is actually picking the car up from the Jack stand that I'm
using to keep the axle from rotating. It is supported by others underneath.
The screws are really dug in, and I don't want to damage the drum or screws by going further. The castle nut is on strictly for protection when the drum does pop off. There is plenty of space. Any ideas or advice is appreciated. Thanks!