Reply to the Vette rear etc:
I dropped the rear subframe out of the car complete and placed it on a large workbench.
Then did the measuring of the pinion snout etc to retain the proper angles for driveshaft geometry. Next, removed the differential and calculated how/where to mount the vette diff. Made a new rear cover from 1/4" steel and fabricated mounts on it.
Then cut the original subframe, but not all the way, to mount a new panel in the middle where the rear of the diff will mount and tack welded it in. Rechecked all dimensions and cut out the remaining of the original section proceeding to finish welding the new section in. Had to mill about 2" off the top of the pinion snout so as to fit it properly to the front of the subframe. The rest sort of fell into place. The axles are spicer joint as the vette's are and sliding splines are used for length changes. Each axle is the same as a driveshaft in a one ton truck!
STOUT!! NO cutting or body shaping was done to the body nor was there a rear alignment done as the hubs and control links were never removed. Most vette diffs come as 3:08 or 3:42 depending on tranny. To change it is expensive/time consuming for setup.
As to the exhaust, I bought a few 3" mandrel bends and some straight pipe and with the use of a bandsaw, cut and welded 19 joints for a free flow 3" system.
The radiator used is a 3-pass, serpentine unit made by Fluidyne, cost about $400. They are located in Cal and here in NC, where I dealt with dimensions etc. Beautiful work.

Good luck...
Tobias MB
C280Sport, 300CE, 400E, 190/5.0