Just got a 727, need advice for a refresh

It may depend on the age of the GV unit as to how much modification you will have to do. The older GV units were somewhat larger than new ones that sell now. I had one that I had previously installed in an 84 D350 2WD truck, that I removed and re-installed in a 71 Challenger. I had to beat the living daylights out of the trans tunnel right between the seats to get clearance. If I remember right (this was 2005ish) the worst points of contact were the top corners of the GV unit itself, plus the top circumference of the bell on the end of the GV supplied tail shaft housing. The GV tail shaft housing locates the transmission mount in the exact same spot as factory. I didn't like how low the tail end of the GV unit itself hung down, so I shimmed the transmission mount up until I was satisfied with where it was. So, my clearance issues were pretty much self-inflicted, but it fit like I wanted it in the end and worked great. With 3.55 gears and 275/60-15 rear tires, my 360 turned 2600 RPM's at 75 mph. Post some pics as you go. It will be interesting to see how the GV system looks up under an Early A body. Another thing that you may already know is, you will more than likely have to beat the pinch weld between the floor pan and the firewall flat to get the 727 to fit in the Early A. The bellhousing on the 727 is bigger than the 904 that came in the car. There is also a rubber bumper thingy in the top of the torsion bar crossmember hoop above the tail shaft that may need to be removed.