Def sounds electrical to me. If you are having a ground issue, it could cause alot of different things. Check the negative battery cable where it grounds to the block, as well as the other grounds on the negative battery cable.
Getting there. Run's ok now. Still need to do the exhaust before I can road test it. I've been side tracked installing wood floors the last two weekends, so the car has been on hold.
Yes. Pulley has to come off first. There is one bolt you cannot access without pulling the pulley. I can't remember what fluid I used off the top of my head. It's on my work bench at home. I'll post back later what I used.
6 PSI should not have hurt the stock head gaskets at all. Make sure you check the block deck also for straightness. Those head gaskets should work for your setup.
Changing the PS pump isn't that bad. The pulley does have to come of to remove the pump. No way around it. Most autoparts stores have the pulley tool for less then $25 if I remember correctly.
Stupid question but have you gotten under the car and looked to see if there is any obvious scrape marks? Look at the drive shaft. Possible the rear brakes are dragging? Pull the rear wheels and see if the inner lip is running somewhere....