May have screwed up installing new cam. Need help!

first, get a tool like this..

Summit Racing SUM-900189 Summit Racing™ Piston Stops | Summit Racing

install in #1 cylinder, carefully rotate engine till the piston contacts the stop... Mark the damper at the zero pointer.... Rotate the engine backwards till it contacts the piston stop.. Now mark that location & remove the piston stop... Measure the distance between the two marks, divide by two & mark the center of the two previous marks..... Remove the stop marks to eliminate future confusion..

Now, rocker cover removed, lay you fingers on both #1 cylinder rocker arms... Without looking at the arms, just by sense of feel, rotate the engine to the point the exhaust valve just about closes & the intake just barely moves, we/re talking less than .010... That is split overlap & should occur at TDC, look at the damper , if you hit the mark your fine, if not take it apart....