I have a rear v8 powered fiesta with that trans heres a link http://www.overbeckmachine.com/Fiest...naIMG_5844.jpg
anyway I installed a 31 spline trutrak and 3.70 gears and with a little metal removal the whole rear-end weighed 78 pounds.
Not too bad for all that iron..
Remember this is a spiral bevel diff, don't know about the vette but I suspect its a hypoid. Way less efficient than what you have and the pinion will be lower or higher by a fair amount.
if its a hypoid flipping it will lower the pinion and therefore raise the whole drive-train. If you don't flip it, I don't believe the axles will clear the crankshaft.
I suspect moving the engine to the rear like that will be making the weight distribution far worse than it already is after all the toro 425 complete with the rear end weighs about 290. If your talking V8 (and you better be or go find a far lighter drivetrain) you will be moving 425 - 500 lbs to a place I wouldn't want it.
The stock configuration works