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