Damn it Laz,
Now I have to ask, "Filter before the cooler or after the cooler?
Two out of three engine builders agree, filter after the cooler.
This is probably one of those proverbial "Six of one. Half a dozen of the other" situations.

synthetic is great so don't get me wrong but we find
that in hyd roller motors it doesn't work (too slick)
rollers tend to slide instead of roll and after a while
starts to create flat spots and stop rolling all together.
now as far as the oil cooler being 3" now i have to go
measure one. you all got me discombobulated

RLW,remember this argument 6 months ago? The only way I'd consider filtering the oil AFTER the cooler would be if you were running big hp6 filters like in teagues drawing. Other wise most filters flow ratings are too close to the flow capabilitys of the filter. In a motor with bypass valves in block plugged while your first idling motor(especially with a BIG cooler) you may open bypass valve in filter. The warmer oil is the better it flows thru the filter hence less pressure drop and chanch of opening bypass valve,bursting filter or stressing pump drive shaft/distributer gear. If you were running a hp-6 with its 20 gpm rating or whatever it is you could run cold gear oil thru it if you wanted so it would be a non-issue,Smitty

If your not running hp-6 filter but have the room run the longest filter you can like I do!

I thought it depended on spring pressure? I'm running 190 seat/450 open w/morel lifters,would this still be a possibility,thanks,Smitty

RLW, My oil pressure drops to 40lbs during a hard run. I am aware of the 10lbs of pressure per 1000 rpm rule and my throttle hand is directly related also. Pressure starts out great and drops as the oil heats up assume. It still maintains 40lbs at idle after the hard run. After giving It a few minutes of idle time or motor around the local raft up party spot the pressure is right back to normal. I guess I am overheating the oil on the 5500rpm range and giving it time to cool back down in the lower rpm range. Seems pretty simple.....I hope! Should I ask Santa for thermostatically controlled larger oil cooler this Christmas?? FYI I am using Valvoline 40wt racing oil.

Thats one BIG A filter

Here is a pic of a stock mpi oil cooler compared to a aftermarket one,I had similar problems when I first started modifying my 502. To give you a idea how small the stock cooler fittings really are I stuck a 3/8 bolt in the hole in the 2nd pic,Smitty

TC,
Still need to know your temps before you can make an educated assessment of your needs.
Get an oil temp gauge for Xmas, too.

Smitty,
As always, I value your input. Basically, if provisions are made (i.e. higher flowing filter) filtering after the cooler is an accepted practice.
Check out the Wix Racing Filter info.
http://www.wixfilters.com/filterlookup/racing.asp
Russ

My oil cooler is even smaller than the MPI cooler in that photo !
Geez.....

I ordered a 3" X 18" cooler Tuesday. Should receive it tomorrow.

RLW, I forgot to mention in my last short story (post) that I have a temp gauge and will be installing before my next trip on the water.