Changing Master Cylinder/Booster on 66 T Bird?!

I wish I had a bit more understanding of what works with what but...:(
I own a 1966 Thunderbird with a 390 FE motor. I am currently having the motor rebuilt with some different valve covers on it. The problem is that the new valve covers hit the brake booster. I dont know if anyone has seen the booster on this year T Bird but its huge! I would like to swap it out with a smaller, dual stage style to make some room. The other thing I would like to change is the master, its still the single reservoir style, which makes me nervous. Would something out of say a newer Torino or Mustang work? Like say a 70s or something? SSBC has replacement booster/master set ups. I dont mind loosing some power assist cause I think its a little over the top as it is.

PS TBird has Front Disks/Rear Drum

Maybe a more generic question will help me with my little issue. Would a 7" dual diaphram booster have the same, or close to, amount of brake assist? I hate math. LOL

Ok maybe if I make a question a bit more generic I can figure this one out. Would a double diaphram 7" booster produce close to the same brake assist as a single diaphram 9" booster?