An update for those interested and question for the Mustang guys.
Did a compression check maybe 20psi between the highest and lowest cylinder. Also threw shop air in the cylinders to listen for anything abnormal, little trash in few of the valves allowing them to leak by, few taps with a hammer sealed them up. Otherwise nothing obvious. Seemed to have misplaced my actual leak down tester.
Threw the top end back together with the recommended gaskets and diy block off plates. Intake is a Edelbrock 4v version, not ideal but seems to fit ok. Fiddled with the pertronix 2 previously installed by the owner. Something seemed wrong, not sure it was seated correctly on the locating pin, can't say for sure though as I decided to just take it off and reinstall. Found a couple plug wires with the terminals pulled off, fixed those ohm tested all wires. Set initial @ 12. Fired it up and really sounds pretty good considering the carb, Edelbrock spread bore (forgot to look which model #) looks horrible, lots of soot/carbon choke wired open. Was just trying to get it running to see if it was hitting on all 8. One thing is the lifters sounded horrible after it warmed up a minute. Oil pressure looked good based on the factory gauge.
Car is I believe a 71 Mach 1. They used the original power wire, jumps around 10v to 12v when running. What is the best way to get true 12v to the coil? My thought was to add a relay using the original power wire to trigger the relay. Any reason that won't work? Can I tie the electric choke with it? I'm guessing no, so maybe another relay.
Hope this week to correct the wiring a little and get the radiator and run it praying it doesn't have a head gasket problem. I smelled some antifreeze at the rear of the car but without the rad installed I chalked it up to the residual antifreeze steaming off a little.