Hydraulic lifter preload...who really checks this?

You saying you’ve only checked bearing clearances in all the stuff you’ve pit together? You have gotten lucky when assembling, if you’ve never checked any of the other things.

My UPS driver has a 55 Belair Gasser with a 502 ZZ with 704 HP from a now defunk shop from AZ. The motor kept eating the #7 lifter. After the 3rd time he changed it out, I told him the motor has to be torn down to find out the issue. That issue is cus shitty rocker geometry and spring was all fucked off. And come to find out JE made the Pistons for Chevy performance, and the piston to wall clearance was too tight once the motor got warm thus causing the 502ZZ‘s to run hot and overheat.