Welcome! The first thing you'll want to do is get the three books described
here and start reading. Tune-up parts and technique suggestions in
this thread. You'll want to remove the rocker shaft and crank the engine to see if oil is getting to the head (if so, it'll shoot out the rearmost rocker shaft bolt hole). If so, then the rocker shaft and/or its bolts weren't installed correctly. If not, there's a bigger problem such as an improperly-drilled camshaft that doesn't index correctly with the oil holes in the rearmost cam bearing). Either way, once everything's back together you'll need to do a
valve adjustment.
