I agree with most of Perry's explanation, however, you may want to adjust to the top of travel and leave it there. I do not add 1/2 turn after the lifter is adjusted. This gets rid of top end float if the lifter pumps up due to higher
oil pressure.
This is a common cheby trick. Install truck lifters and adjust them at the top.
It is even better if the engine is running and the lifters are fresh.
Good luck.
Just my $0.02
