I bought a gear vendors overdrive for my dad for his 62 Ford Galaxie. His car has a Borg Warner T10 four speed. When I bought the 'kit' I was told it was a drop in install and all I had to do was put a shorter output shaft from a Mustang in the T10. I found and bought the shorter output shaft, Dad and I pulled the T10, tore it down and swapped in the shorter shaft and installed the Gear Vendors tail housing. We then went to put the trans back in the car. There was no way it was going to work. Both the shifter and the trans mount were totally in the wrong spot. I called Gear Vendors and they said 'sorry, we were wrong. You have to swap a Toploader transmission in the car to work with our overdrive." We pulled the T10, tore it down, put it's original output shaft back in it and put the car together. We shipped some of the Gear Vendors 'kit' back (tailhousing adapter, etc.) and they sent their stuff (tailhousing, shifter brackt, etc.) to work with a toploader. I find and buy a toploader for the car in the meantime and rebuild it. I get the new tailhousing adapter from Gear Vendors only to find the toploader output shaft is too long. I call Gear Vendors and they say "we meant to tell you that you will need to put the Mustang length output shaft in that toploader for it to work." At this point I'm pretty frustrated. To Gear Vendors credit they tried to make it right and sent me a new output shaft they sourced from a vendor. So dad and I tear down the toploader and install the shorter output shaft, tailhousing adapter, pull the T10 out of the car and install the toploader only to find the gear vendors overdrive unit won't fit because of dad's stock style h-pipe in his exhaust. We also discover that while the shifter is in the right spot, their bracket has it needlessly angled way forward which won't work with the stock console and the transmission mount pad is way too short so a very thick spacer will have to be fabricated to correct the driveline angle. So the next thing we did was to put the T10 back in the car and drive the car to an exhaust shop to have dad's stainless h-pipe exhaust system modified into true duals. At this point I think we can get it in but it will require trimming of a floor brace, the spacer for the trans mount I mentioned, some engineering on the shifter, shortening of the driveshaft (we knew about) and who knows what else. Long story short it was not a drop in as advertised, rather it's a totally custom install. Gear Vendors will tell you what they have to in order to get the unit sold. I spent around $4K trying to do something nice for my dad and it has been a nightmare. On a car like dad's, it's about the best way to get overdrive in it. On something like a g-body, save money and headache and do a transmission swap. I should have done more research before buying the Gear Vendors. Lots of people online complain of vibrations from bad driveline angle after the install (numerous different applications, both manual and automatic). If you have the talent and the persistence the unit can be installed but it is not a bolt in deal. Sorry I can't tell you what it's like driving it yet but wanted to share my experience in case you are thinking of going that route.