.030 5.9 magnum
I'm wondering if maybe your rebuild was done with a set of .030 360 flat top "LA" pistons and not Magnums and maybe a lower compression part? Factory Magnum pistons look like these on the top.
Checking piston to block clearance.
[ame="http://www.youtube.com/watch?v=0VsjaY4PBMg"]Checking piston to block deck clearance.MP4 - YouTube[/ame]