harsin

How many hours can I expect to get out of the bottom end of a HP 500, and what typically needs replaced on the rebuild? Thanks

mcollinstn

Regular oilchanges, keep it out of detonation, keep it under 6000rpm, and the bottom end will go well over 500 hours no problem. Should probably see more like 800 hours if you want to push it.

Supercharge it and run it into detonation? Hammers the bearings and knocks the big ends out of round over time.

Spin it over 7000? Do that for a few hours and you'll be able to inspect the inside of your motor "from the outside".

What needs replaced at a normal service interval?
Depends on what your goal is.

Full-on rebuild will line bore the block, recondition and rebalance the rods (big ends). New rod bolts (of course), and new bottom end bearings (clevite H is a good choice). Shouldn't have any need to grind the crank, but you may want to have it cleaned and micropolished.

Cheap rebuild will just knock the old bearings out and throw them in the trash, rub some crocus cloth on the crank journals, and toss in some new bearings.

Your choice.