It isn't exactly apples to apples, but it isn't apples to bowling balls either. My stepson is driving his 68 Sport Fury, 318, auto. He has manual drums, and wants to keep it that way. But that is beside the point I wanted to make here. I have a 1990 Dakota Convertible. According to the local scales, his small block Fury only weighs 100 lbs. more than my Dakota. I would hazard the guess that the master cylinder, (2 bolt) and booster would be very similar in size for the C bodies.
9" Makes a difference! (I could not help it. Cheers and good weekend!)
Thanks, All. I feel better upgrading, now, instead of insisting on the period only. The limitation (not insurmountable) is the metric attach for the brake lines. I may look for some brass adapters... ?