54 car motors came in two flavors. Motors that came with a stick shift got a block with solid lifters. Cannot retro fit hydraulics. If the motor came with a cast iron powerglide, that motor came with hydraulic lifters. Powerglide Motors can be retro fitted with solid lifters. Solid lifter motors can not be retro fitted with hydraulics. You must be absolutely certain what kind of lifters your motor has.
With solid lifters there is a bit of clearance that is necessary to take expansion of the parts as the motor heats up and for a margin of safety because there is no give with solid lifters. That is the clearance setting. You get this from the 54 shop manual
If your motor is a 54 car motor with hydraulic lifters, you need to read the 54 car shop manual for the procedure. There are other ways to adjust hydraulic lifters but the shop manual is the first place to start.
