For what it's worth, Mark Donohue in his book "The Unfair Advantage" talks about how they tried this on their TransAm Camaros and never had any success with it and rated it as a big time-wasting failure. But, probably the easiness of doing this depends on the variations in design of the live axle between manufacturers, and besides I'm sure we're all smarter than Mark Donohue anyway ;-) As another aside, the english Mallock cars used live rear axles for many years in preference to IRS and there was an article about 10 - 15 years ago in Race Car Engineering about all their "magic" tricks to make live rear axles work very well for road racing, you might want to find that...