H or P main & rod bearings
 

Got my block back and the machinist's counter person gave me Clevite P mains and rod bearings ("because that's how they've done it for 50 years" type place).

I've read on here that H series are better with certain crank material and horse power ratings. This is going in a gen 5 -525SC rebuild should be about 600hp with a forged GM crank and Molnar 6.358 rods and JE flat tops, plan on running it around 4k to 5k with 5,600 to 5,800 RPM max.

What's better Clevite H series or P series for my application?

Thanks

The machine shop that just did all my work would not install P bearings in my motor as that's what I brought with it and frankly I didn't even look at them...I bought them from a performance shop along with all my other goodies and assumed they were right...NO!! lol they replaced them with H bearings....I hope I don't have this backwards but from what they said the P bearings are normal Passenger car bearings...The "H" bearings are High performance and like I said they would not assemble it with P bearings....for what its worth that's my experience lol

100 years ago there weren't any H bearings. We made a fixture to cut the P bearings for the bigger fillet radius on our cranks and lived happily ever after. At the time is was 6000 and up to 800 HP.

So - I think if you have a crank with stock fillets the p will be fine.

Dang I thought I was old..................^^^^^^^.......:D

Really depends on the crank being used. H series are needed for most performance cranks with a radius on the journals. If the crank has no radius then a P or H will be fine. Clevite markets the H bearings as HP so with your setup I would errr that way.

Bingo, all depends on the crank. the materials the same just the H have chamfer for crank filet

i use p bearings for factory gm crankshafts all the time but if spending double for h bearings makes one feel better they also work well.the power output really does not come into ply.edit in,the materials are not the same,the p bearing is a little softer on the crankshaft side and has better ability to imbed dirt that is in the oil.

How can I tell what will work, do I need to measure the main & rods width and radius on the crank?

Mike, are the P bearings good to 800-850 HP?

if you have a gm production engine crankshaft the p bearing will work no matter what the power output is,if you have an aftermarket crankshaft you need the h bearing.also note the h bearing offers about .0005 extra clearance over the p bearing.