Took Lil' Red for the first drive....few issues

[jimmybeus]

I finally got my 86 k 10 up and running today. I put in a rebuilt motor and shift kit in the 700r4. My issues are When I first got it running three days ago it had awesome oil pressure. It was right about 50 on the gauge. Started it a few time over the last three days while finishing up the exhaust and few other small things. Today When I took it down the road the oil pressure was only 5 and would go to 30 while driving but soon as it would shift the pressure would drop and then pick up as the rpms would come up. I am running Royal Purple 5w30 and a K&N filter. What would cause this?
The next issue is my temp sending unit. I located the correct wire for the sending unit but it was reading almost in the red after running for about ten minutes. When I shut the truck off with the lights on the gauge would peg out all the way to the right, pointing about 5 o'clock position. I spliced a new wire from the fire wall to the unit but same results. Any thought s on this? Other than those two things it runs awesome. I hope to post pic tomorrow.
Thanks in advance

[PRattenbury]

Hook up some mechanical gauges temporarily and get the true readings on your oil pressure and coolant temp. Make sure everything's okay first and then worry about the indications you get on the stock stuff.

[87GMCChris]

My stock oil pressure would read zero after few miles... put an high flow pump and a mechnical gauge on it. Idle hot is 20lbs. with rpms its close to 40-50, and cold its more.
I went with the high flow cause mmy engine is original and 240 000 KMS. I figure with worn parts it could only help. As for coolant... mine fine, so i don't know what to tell you other than what PRattenbury said with the mechanical gauge.