what you really need is a quick change center for your A-ford rear...
which is easy for me to say as i am not going to listen to the constant whine..
to be perfectly honest a hot rod is a work of art, not a car that should be built to a certain spec. so if you have a rear end from a toyota with the gearing you need, stick it in there.
personally i like the jaguar IRS as it is indestructible, has disc brakes, looks cool and makes for a much better handling car. (i even heard that national drivetrain has a mountain of centersections in various gearing for 50$ each.) if you like i can e-mail you a battle plan for fabricating brackets and so on.