Thanks for the above suggestions folks. (appreciate all of the insight)
Rob, I have mounted MSD boxes in the glove box of a few cars now and will run a hidden MSD for this one as well. Last time I routed the wiring under the heater box on the far passenger side and through the firewall just to the right side of the inner box where it tucked straight into the glove box liner. I will likely do something similar to this car and it should be far easier with the fenders off.
This is by no means a purist type build so power will come from a remote F*rd solenoid that will mount in an obscure spot on the passenger side of the firewall. I like to run a high torque mini starter and the solenoid w/ relay provides clean power that's tucked away from any heat source. Tach will wire from within the car as the feed then comes off the MSD box. I do like the way Freddie ran wires in the harness but I need a thicker gauge power lead for the MSD and that must come hot from the battery. Using the late model ignition box, I then become very picky about making the whole thing hidden and discrete.