I would be very concerned if the flywheel is moving, forward or backward. As the flywheel is attached to the crankshaft, that would mean that the crankshaft is also moving. What is the allowable crankshaft endplay on a Model A engine? Would this not indicate that the crankshaft thrust bearing is...
Go to your local Napa store. The exhaust catalog has all their mufflers listed by dimensions. Ask the counterman to let you look at the catalog. They should be able to help you.
I may be way off on this, but see if an early 55 or 56 Chevy, V8 Cap will work. The early SBC Cap is different than the later ones with the screw mounting.
I used to do a lot of parts business with a local tree company. Their chippers all had 4cyl. OHV Ford engines. This was in the early 70s. These engines were the same as a Ford 801 tractor used.
Go to your local Napa store. Have the counterman get out the brake hose buyers guide. In this catalog you will find descriptions of all the hoses that Napa lists, by length, type of fittings and any mounting brackets.
Make sure you have some free play in the master cylinder rod. If the piston in the master cylinder does not completely return all the way back in the bore, you will have the problems you described.