Seems pretty normal for marine engine. Mine will drop to 18psi sometimes .. oil cools and it comes back up with some rpm

stock cooler that was sized just big enough to keep a stock engine at a reasonable temperature. It all cpmes down to hp equals btus/heat/friction. I have had a few customers were we increased their hp from 415 etc to 600 and used stock cooler. The oil quickly heats up, when running it hard, keep your sustained wot to short burst, install a oil temp gauge. Problem is it probably never stabilizes IF you kept it at wot, ie, if you held it for 20 or 30 minutes at wot it would probably blow up eventually where a blower engine properly tuned with big enough cooler will usually be able to hold sustained wot.

Tom,

I'm thinking I will be leaving that to the more adept and compact.

Thanks. Brad.

Knot,

I've got that part down. did it five times in a matter of a couple weeks when I was trying to root out what turned out to be bad injectors. One is a serious PITA to get to, but, all-in-all, it ain't too bad.

Thanks. Brad.

Smitty,

I rarely run it hard for more than a couple minutes, if that. I'll be looking into splicing in an oil temp gage, though.

Thanks. Brad.

It's good to know that 20 lbs after a hard run is okay.

PQ290,

*At idle....

Thanks. Brad.

Similar story with my 502 MPIs - they’d drop down to 20 or so at idle after a hard run. I’d kick the idle up a little to cool the oil a little quicker. That was with Mobil 1 15/50. When I took it all apart to do the new builds, the bearings looked excellent. They had about 400 hours on them.

I've run multiple build combos of supercharged 496HOs. They need a larger oil cooler. I can't stress this enough. Put an oil temp gauge in. If using the factory oil filter mount I drilled the base and installed the sensor there.

I've done a bunch of experimenting with the oiling systems on the 496HO. I ended up with a 3''x18" oil cooler, -12 lines, and an aftermarket high flow oil filter base in order to keep an 800HP one cool. -10 lines and the factory base worked to keep a 600HP cool using a 2.5" x 19" cooler.

Just a tip: I repurpose the factory engine oil cooler and use it for the power steering cooler, this frees up the rear of the engine for a larger engine oil cooler without doing too much modification to the factory water routing!

Be careful with your temps!

Right on. The stock cooler is adequate for a "stock" engine. Oil temp gauge is your friend.