Hey guys!
So here’s the concern- I did my first WOT pull on a new motor yesterday, dropped back down into the no-wake and my oil pressure at in gear idle was hanging around 3-5 pounds.

A little background... there’s about 2 hours on this engine. It’s a 468, 4 bolt, cast crank, flat top pistons, Comp 262/268 112° Flat tappet cam, roller tip rockers, double valve springs on peanut heads.
I’ve got Sierra 25-40 oil in there with 2 bottles of Lucas break in zinc additive. Did the cam break in at 2500 for 25 minutes.
My WOT run was under 7 minutes with 60 PSI at 4600, 155°. I tied up for an hour after, then when I went to trailer up I had 40 pounds at idle headed back to the dock. No hose blow ups in the engine space, cooler, hoses & remote filters are all happy.
Any ideas what happened there?
Thanks for any input!

My WOT run was under 7 minutes with 60 PSI at 4600, 155

155 WATER TEMP OR oil TEMP? HUGE DIFERENCE.

155 was water temp while under throttle.

Verify with mechanical gauge

What oiling system/oil cooler? Your oil temps were likely thru the roof and thinned oil to a much lighter weight than 40w.

Is your oil cooler new or from previous motor?

Chris

Remove and Cut filter apart before running it again with mechanical gauge , if nothing found in filter.

Speaking of the filter, what brand and what number did you use?

Sounds like your oil cooler is undersized. Some oil filters have a paper medium non friendly for marine use that swells and chokes the system, but my guess is your oil got cooked.

Thanks for all the input!
Sounds like a bigger cooler is in order.
I’m just running an OE Merc cooler then taking off with -10 AN hose to a Deralé dual remote filter housing.
I’ve just got some low-end O’reilly filters on there now but will switch to Wix racing tall filters after I change out the break in oil.