At what point should one go from std to hp cam bearings?
Spring pressure, etc... ?

Thanks

As far as I can tell, the best cam bearings are the seamless ones, made by DuraBond. I'd say use them on everything.

Be aware that some blocks will have shifted during the thousands of heat-cool cycles and the bearings aren't exactly concentric. Put a new cam in and it is very hard to turn with no lifters or oil pump.

There are three methods to cure that and the theoretically better way is to line bore the cam bearing holes and use special oversize cam bearings.
The second way is to scrape the cam bearing using Prussian Blue and a sharp edge like a single edge razor lade or a cam bearing scraping tool.
Another way is to modify an old camshaft with diagonal grooves on the journals, essentially turning the cam into a cutter.

R.

Yep, I've had to knife cam bearings before. I was just curious as to what performance level would require an hp bearing.

I've used two sets of Durabond "Chilled" cam bearings in BB motors, one 4.5 inch bore World wedge block with B1 heads with a big solid roller cam and the other went into my latest 400 block stroker race motor. Both sets of heads have over 300 lbs. on the seats and over 800 lbs. over the nose My 400 motor and the B1 motor will rotate over a bunch easier with the plugs out than any other wedge motor I've built with regular cam bearings in them with similar spring pressures Roller cam bearings are suppose to be a bunch better than any standard type babbit cam bearings
IHTHs

I didnt even know they still used ones with seams any more but I bought like 40 sets of the mopar performance ones years ago and have been pulling off them and not bought any recently, but do need to buy a oem type set for a job.

Probably just dumb but ive never had to shave a cam bearing but I have had a cam every now and then that must not be fully straight because they have a hint of drag when installed vs other cams in the same block, ect.

I think cam flex would impact most any bearing semi equally.

Thanks Cab
I don't think I'll be running anywhere near those pressures on the next build.

I had a roller cammed hemi beat the #4 cam bearing out oval once. Now, I use hardened coated bearings on everything for which they are available. For 20 bucks more, why not?

Good point!