I found a picture of the hardware I used for mounting the MSD to my firewall-
I don't remember exacty what size the studs were probably #8 or #10. I bought them at my local TrueValue hardware store. They work really well. Use a little silicone to seal the holes where they bolt into the wiper cowl compartment. The wiper cowl has to be removed for installation, obviously, and it is a bit of a trick to get the holes started for the drill, but a real good smack on the center punch should keep the drill from slipping since you can't get a straight shot on drilling the holes.
I used the black corrugated cover for my wiring and tried to follow existing wiring to the coil.
For the "hot" wire I ran it to the terminal stud in the engine compartment electrical center. The one in the right rear is not used, so I added the maxi-fuse to power it and attached my wire there.