Advice taken...slowly the mystery build will be unveiled.

Screw that, if you paid for a comp. test and got results as if they did it I'd force them to buy the boat from me for the price I paid for it. Someone would be taking that POS back from me especially if I had a written bill of sale documenting all of the parts that were supposed to be included that the seller removed. Lawyer up!

I'm going forward with an autopsy and rebuild...leaning more toward reliability vs. performance if necessary. Not knowing IF the crate motor has the correct oil filter by-pass, I will order the correct one(s). I've read some varying answers even on this site. So including the part# for the correct 30# bypass valve...to encourage more (not all) oil through the filter...can someone show me the parts shopping list for a Gen VI 502 block? I want to hand them to the engine builder and rule out that possible repeat mistake. Is it one or two valves? I'm assuming I won't need to force all oil through the filter. Finally, I most recently used the Napa Gold 1060 filter...was that ok? Thank you.

Nothing wrong with that filter. Wix makes it.

So is gm part #******** (edit/25161284) (30#) all I need to swap in??? Do I need one 30# bypass valve for the oil cooler line, also?

as i was waiting for this answer...and preparing the boat for the motor yank, I see that my oil circuit currently goes from block through the OIL FILTER 1st.... THEN into the OIL COOLER 2nd... then back into the block (center of adapter)...IS THIS OK & should I repeat that route next spring when it all goes back together??? I swear I saw a schematic showing feed the cooler 1st THEN the filter...but now I can't find it.

and once again which bypass valves go in & at which location? I assume none of these bypass valves are at the remote filter location? IS this correct: at the block location: remove the center return bypass completely & install the 30# bypass @ the side (outlet) location (which currently feeds my filter 1st). I know I'm starting to talk like Trump ;).

Pretty much everything that you need to know is right here.

http://www.offshoreonly.com/forums/g...-hardware.html

Cooling the oil before or after the filter is debatable but not an engine killer.

Can't be mad about that. Those 500s were the best blue motors.

I found this a handy reference.

http://i1166.photobucket.com/albums/...pslkrodntd.jpg

Sooo if that's the "bible", doesn't it show the 30# bypass part # incorrectly? Here it is:"If your running a gen 5 or 6 block and it started life as a crate engine,it has 11lb bypass relief valves. If your motor has unknown origin,who knows what it could have. Buy a new 30lb bypass relief valve for the outside(the one near edge of block casting for filter adapter) or plug it off,they are available at your local chevy dealer part #25013759,they are under 5$."...
I have seen that valve part #25013759 described as the oem 11lb. valve AND part #25161284 as the correct 30lb bypass...No wonder so many builds get jacked?!