make double sure you note where the screws & bolts go on the radiator. the 3 that hold the fan are SHORT... if a longer one is installed it will drill a hole in the radiator that can not be fixed. looks to me like the rad may have had a problem? the glue spot suggests that. also the cap looks like it has sealer residue of some kind.
there are no rings for the stock Gen I piston (unless you get really lucky)
call Eagle Mike... he may have a head, rings, etc
ps... you can let the cam chain drop into the hole & pick it up later with a magnet. it can not jump off it's gear on the bottom