oil pressure acting odd

I have an amc 304, and just got done reading all the posts about oil pressure. Glad I'm not the only one with problems-- but wish there was a chaeaper solution. My problem is a little different, my oil pressure builds up fast when the jeep is started but then (about 70-80lbs) falls quickly to less than 10psi. My relief valve isn't sticking, at least not while it is on the bench. Could it just be the spring is losing its strength? Do you suggest buying one of the high pressure springs? And would I be wrong if I assumed that there is nothing wrong with the gears/pump itself considering it builds up to 75 psi initially? I just had it apart and am pretty sure that nothing is plugged. Any help would be great, thanks!

When you build excessive pressure and then it drops drastically when warm you either have a sticky pressure relief, stuck relief or ad pressure sending unit. 70-80lbs is not good in a AMC V8 with a stock oil filter adaptor from 86 and older.....they have a dreaded oil filter bypass that will roach your bearings.

I bought a new relief valve spring/plunger and new gears. I checked the tolerances and the gear to body was about .0015 the gear end clearance was about .005. according to my book that is within specs. The pressure dosen't jump up high and fall like it used to, but unfortunately it only gets up to about 10psi. (and that is with cold oil). I know my gauge isn't bad because I have a manual gauge tapped into the dummy light sensor hole.
I put new main bearings in this winter, (they are the correct size) so I'm pretty sure my bearings aren't the problem. Has anyone ever had a problem with the pickup tube being too close to the bottom of the pan/ or just having it in the wrong spot? That might sound dumb-- but I'm getting desperate. If you have any other ideas or know of some sort of external pump that I can drive with a belt... (ANYTHING PLEASE!!!) I'm a big AMC fan but this V8 Oil issue is crazy :!:
also that bypass valve that you said would roach my bearings---it seems to operate fine---that wouldn't have anything to do with my low pressure--- would it? It is the stock adaptor and it is older than the year you said.
Thanks for taking the time to read this long sob story.

There was a post where someone was talking about the pickup tube being to close to the pan. If it is it could possiably suck the pickup to the bottom of the pan. The tubes should have a plastic "button" or somthing like that, that keeps it fron getting sucked to the bottom of the pan. That might be somthing to look into.

There are two bypasses on your oil filter adapter. The pressure bypass and the filter bypass. The pressure bypass is the one that came with your pump rebuild kit. the filter bypass is where the filter screws onto the adapter. When you remove the filter you will see it. there is a teardrop shaped peice of metal under the part that the filter threads onto. you can remove the filter threads with the correct deep well socket to get to the filter bypass. I am building a 401 and I just caped off my filter bypass. Read here for a little more info on that: http://www.bulltear.com/forum/viewtopic.php?t=3996