timing/tune up problems

................. the mixture screws have lil to no effect on vacuum or rpms, even turned all the way in.
I'm thinking i have too much initial timing causing high vacum and drawing fuel into the carb???

No way in heck that this timing/ carb relationship can happen

I don't trust "dial up" timing lights and there have been problems with various lights with MSD. If you can, bypass the MSD until you get things settled down

The idle screws not having effect could be a few things

Too much fuel pressure driving fuel past the needles, too high float level, or other problems causing the float level to be high

The metering rod springs may not be seating at idle, remove the top covers and see if this is so.

Has the carb been hacked? IE someone changing jets/ rods/ springs?