He still needs to check that ground wire on the backside of the engine.

Yes,...but because it feeds all the sensors, it'* most likely not the cause of his instrument cluster issues.

Location of the ground wire? High/low, fastened to the firewall, fastened to the battery, back or front of the block? Will try and look tonight.

Is it possible that the cluster is whacky although I have never heard if this. It'* just odd that the flakyness all started with the engine swap.

I test drove tonight after doing the work that I did, I also forgot to mention that I removed and reseated the main electrical connector where it goes into the cowl. After all of this there was still no change as expected.

I still didn't check the main engine ground, I had to clean the garage before I could do any more. I'm still puzzled why my volts and oil pressure drop as the RPMs go up and the wiper fluid and check gauge lights come brighter with RPMs. I did notice that my alternator is making a little noise now.

I found the ground near the starter and I spend an hour looking for the other one that you mention, I can't find it anywhere.

UPDATE: Installed a manual pressure gauge... I have 50 PSI at cold idle and it drops to 42 at hot idle. No matter how hard I pounded on the motor, I got no less that 20 psi in gear, at idle, and after an hours run.

A new twist, if I really put my foot in it the check washer light and check gauge lights still come on as previously mentioned, but as the RPMs get up there pretty high, it starts to miss. I'm convinced this is electrical of else I would just put an under dash oil pressure gauge on it and forget about it.