I'm trying to remove the remaining distributor rotor which appears to be seized. There is a philip srew that I can't remove. Is it work fixing it or should I buy a whole ignition unit?

First, apply a small amount of Kroil or PB Blaster to the machine screw and let it sit. Then, use a precisely machined #2 Phillips head screwdriver. I use a Wiha bit holding screwdriver, with a #2 Phillips bit. It works perfectly--the precision ground tip fits like a glove and its magnetized for perfect extraction.