Low Oil Pressure,Rebuild...

ok, well replaced the sending unit, and no difference, put a new fan/clutch and now the temperature comes down but still hangs close to the 250 mark at idle ..... ut it comes down and never did that before, so i am really going with bad radiator........

but my next issue is oil pressure..., maybe coincidence or not? after replacing the oil press-sending unit, it had a hard time starting and stumbled....but then ran fine,
i drove it around town fine pressure needle on 0 and goes to 0 immediately after the engine gets warmed up enough to move the temp gauge...so it starts at the R (noRmal) mark and goes to 0. i grounded the wire and did key on and the gauge went all the way up....thats why i replaced the unit, but actually worse than any better....so im guess this means bottom end trouble,,,,i am going to hook up a cheapo mechanical to see what im at as far as pressure, but i think the oil pump quit...

last but not least i could not get it to start in the gas station, it kept spinning over, but nothing, i hear the fuel pump buzzing,,,,,,i let it cool off, and finally it fired up, much like a carb'd motor...it then runs fine,,,,now the fuel pump is no longer making the signature high pitch buzzing but kind of like a low pitch grind...

im pissed,upset,and broke....what to do...
ps. and a for sale sign is looking nice

edit:
installed a sunpro mechanical and i'm running at 15-25psi of oil pressure warm at idle and the most i saw was almost 28-30 @ 5k.... .............

so i guess its bearings and oil pump time....i need recommendations for parts etc. i want to do this right the first time....do i have to remove the tranny to get the oil pan out...can bearing be done from underneath the car???what brand/size do i need...

also was wondering if running some 20w-50 would help, or maybe since i was overheating the engine oil is way to thin???!?!?!? any ideas or suggestions are always welcomed...
jsut give me a starting point, before i sell this car....(NEVER!!!!!!!!)

come on guys i need some advice

i kind of figure doing a main rod bearing job is impossible from under the car...and i am searching around to read that even removing the pan for a oil pump is a PITA.....if i pull the motor, the car is going into complete overhaul mod.....clean up the bay a little and freshen up the whole motor.....

but at the same time i cannot afford this!!!! so it might just be thicker oil and cross my fingers, or just shutdown the car for a long long time......i have been reading that just a new pump might not solve a low oil pressure problem, and i would hate to do that much work and have no positive results...im still waiting for responses on what to do or opinions to at least start a blue print...

okay, for those that care;
i put in some 20w50 gtx.....got to 50-55psi cold, then still about 25-30psi warm but now when i rev it from 3k-5k its moves up to 50psi....( really like the mechanical gauge )
that is a big difference,at this point I'm really just going to ride it out...if i continue to get 25-30psi at warm idle and 50psi revving/cruising then i cant complain @ 156k...
i still however need a new rad and appears to me a overflow tank to defeat my slight overheating problem.......
and oh yah, when i opened my hood to my surprise a nice 100+ fireant family with eggs in the fins and on my intake.........now they are in the car somewhere, any ideas of a place to check/spray..