what can i do about low oil pressure according to gauge it drops as it gets warmwer way past zero where do i start

that era of 5.0's were known for weak oil pumps that wear out over time. the proper repair is to replace the oil pump. To buy some time you can try using a thicker oil (now that its summertime) such as 15-40 and use something like lucas oil stabilizer. but this is only a temp fix to buy you some time.

replace oil pump

You can try a new tube type gauge to double check the pressure. Don't procrastinate about this issue very long, you could ruin your engine. If the pressure is too low, you may need a new oil pump,pronto.

Could be oil pump or big end/ main bearings are worn. Is there. Nocking noise? Never rebuild pump tolerances will be out.

put a mechanical gauge that you know is good on it 1st, and if the pressure builds with engine load then its fine for the time being

oil pump is definately answer i did the same on my 83 also fords and chevys are notorious for leaky intake manifolds and ur truck could also ur truck could be havin backflow which indicates bad valve seals all that should help but just focus on oil pump then add some Lucas oil to it and check the oil pressure regulater too