OOPS ! ! ! Shoulda read the whole thing and not skipped to the end.
Anyways, the post is still righteous and might help somebody in the future.
Get yourself a remote starter switch (any auto parts place or even H F). Then you can crank it while leaning over (NOT on) the fender while checking for spark. I suspect you know that changing the head gasket can NOT affect the valve timing on a flat-head engine unless you did something on the front of the engine that you didn't mention. The tip for finding TDC is dead on. The only things I would add is that you hafta make sure that it's TDC of compression stroke (both valves closed, old flat-head tip - bust the end off an old spark plug and remove everything but the shell that screws into the head. Find a piece of hose that fits over the shell and push it on. Screw the shell into the head. NOW, when you bar the engine over just put a digit over the end of the hose. When it doesn't "blow" your digit off it anymore, insert the wire mentioned above through the hose and shell. Finalize TDC. NOW, pull the wire and blow into the hose. If air goes in yer a full crankshaft turn offa compression stroke, or . . and I hope not, yer valves are sticking open.) only NEED to do it for cyl. # 1 for the purpose of checking rotor and cap (wires) position. If ya can't blow in, double check where the rotor is pointing, and the points should be closed, or very, very close to closed. The rotor should be pointing at a cap inside terminal. If yes to previous, install cap and follow firing order for installation of remaining wires. Put the plug back in # 1 and ya should be golden. At least as far as ignition electrical is concerned.
Do a leakdown test, or disassemble the engine and start over. That' ll NEVER fire with those numbers. Doesn't sound like a chain jump, and just a compression test won't tell ya anyway if yer tester is the "keeper" type that holds the peak (via check valve) regardless of how many times ya spin it. No disrespect to the mighty Carnac ( he knows my future ) but I am gonna go out on the "there was something wrong besides / or along with the head gasket before the repair attempt" limb.
Every no-start gets a compression test and, if low like this one, a leakdown test before ANYTHING gets replaced. If not, more often than not, ya end up throwing parts at something ya missed the first chance. Or, like the beloved Carnac, ya get frustrated and unload it. Glad that THIS time it's going to a caring home. So . . . to wrap up, DIAGNOSE COMPLETELY, then decide on course of repair. Eliminate everything that DOESN'T need fixed or replaced, . . . then fix or replace everything else. Simple right ?