Jags used the 4 3/4" bolt circle, and GM transmission for a while (to cure the problems they had with their own trans).
The IRS is in a complete assembly and really quite easy to put under a vehicle. Not sure on the IFS. Although, I say do it. It is much stronger than a Mustang 2 IFS, although not as easy to install as my IFS kit.
Did you find the engine yet?
