Re: Replacing a oil pressure switch
Your oil pressure sending unit is against the firewall, under and slightly to the right of the distributor. You'll want to preferably remove the distributor, but at least the cap. Prepare to lay on your motor, get grimy, and swear a lot. The part is about $18 from an auto parts store... I can't remember if it's 1/4" or 1/8"... I bought both, and returned one. I just don't remember which.
Good luck.
If you remove your distributor, it has to go back in on exactly the same teeth it came out of.