[svandamme]

the dizzy should be pointing to whatever the #1 wire was connected to
it is possible, to put a dizzy in so that #1 points to another angle than it should... maybe the PO did this

at TDC for a cylinder, both intake and exhaust valve should be closed
that's the only way to be sure

with both valve covers off, it's viewable
rotate the crank
and watch the intake open on #1
right after that , it will close
both valves should be closed now
and the mark should line up on the crankshaft pulley
voila , TDC for #1