Idle screw question. Rich or lean?

Years ago, I worked on an 84. I think that was the first year of the EFI engines. That 4 speed cam in 84 was pretty jumpy down low. Being EFI, I couldn't do anything with it.
I'm having a hard time accepting 18/19 inches vacuum at 750@13* idle-timing. I would have thought a lot less.
Without the specs Ima thinking the timing is not 13, I'll have to see if the web can find me specs.