Im pretty sure you are going to have to change the input shaft and output shaft of the trans due to the different spline counts between GM and ford. Plus the GM version uses a hydro actuated clutch while ford uses a cable actuated one in its mustangs, until the 05's came out. Also you have a mechanical speedo while the GTO is electrical. Might not be worth the money. There was a cobra T--56 on craigslist for 1900. I know its more money but by the time you do all the stuff to the GTO trans you might be in that ballpark anyway.