...so based on lots of intel I'm planning to 'bolt it up and go', but here's some gee-wiz info regarding lifter preload...

My 360 ran nice and quiet before pulling it, and I want it to be just as silky smoove this next go. I wanted to get a 'baseline' for my OE lifter preload - it seemed to be just right before, so may as well try to determine how it 'was'.

With the OE cam still in, I reinstalled two of the restored lifters, laid on the old head gasket and bolted on one of the heads (tightened down 'snug' but not torqued), installed the rods n rockers loose, tightened the rocker bolts to 'no-slack', then measured how many turns the bolts needed before hitting 21 lbs. And a pic 'cuz that's how we roll -



Both exhaust and intake rocker bolts made 1.75-1.8 turns before hitting the spec of 21 ft/lbs. The question thus is..."ok...but how much pre-load is that"? Apparently it was just right - the engine was quiet at all times, so I can only presume it was 'good'. Not very scientific but there it is. I've been told that between 1-2 turns is 'good'.

My new Comp cam is a new core (not a re-grind), and has just a bit higher lift...and I think that is achieved by grinding the base circle 'down' (compared to the OE cam that was in it), which means the lifters will be 'further away' from the rockers than with the OE cam, so with the same push rods there'll be more distance between the rocker cup and base circle, so that means I'll have less pre-load, and according to Hughes Engines the lifter pre-load spec for a 5.9 magnum with hydraulic roller lifters is 0.080-0.095". In theory I'll have even less with the new cam (presumed lower base circle, but maybe not if there was 'room' for a taller lobe - don't know), possibly going the full 2 turns.

At any rate, IIUC the hydraulic nature of the lifters can 'absorb' minor inconsistencies like this, and based on several sources I'm going to bolt it up as-is, but I figured I'd just pass on what I'd found.