I have a 51 brougham and 1984 Corvette front and rear suspension.

supersix

Has has anyone ever installed C4 Corvette suspension in a step down ? 

squirrel

I stared at the rear axle on my 51 and decided it would be hard to find an axle from another car that would be narrow enough to fit. I think you may find that the Corvette stuff is just too wide for the car. Get out your tape measure, see what the answer is?

50C8DAN

I am putting a C4 rear and front in my Studebaker pickup.  You can get Progressive Eng. to help you out in making it fit, they make custom kits for this very purpose.  Bob there is very helpful: https://www.progressiveautomotive.com/installations-kits-parts/front-suspension.html#

40indianssgmailcom

I am using the tried and true jaguar xj6 IFS and IRS in my 47 hud pu.  It is a nice fit