[6567GTO]

I recently installed a TKO600 overdrive trans in my 520 hp 65 GTO hardtop coupe that I bought from Classic Chevy 5 Speed in CA and thought I'd share the experience with you all.
In total I'd say the job took a couple days to do by myself. If you have a reasonable amount of skill working on cars you should be able to do the same thing in your Pontiac without too much trouble.
I chose to go with a .64 5th gear ratio. They also offer a .82 road race ratio.


The Installation:
First I removed the front half of the interior including the seats, sill plates, kick panels and carpet. I then jacked the car up as high as possible to allow for ample room when removing the old trans and for installing the new. I placed the jack stands under the rear axles and under the front spring lower A trays. Next I disconnected the exhaust which is an aftermarket system. Then I removed the driveshaft followed by the shifter and then the Supercase Muncie. I decided to leave the clutch assembly alone at this point because it was working just fine and therefore left the scattershield in place as well.
I then climbed back into the car and traced out the area which I'd need to cut on the tunneling to clear the new Tremec. Tremecs are a little larger and boxier then Muncies so this part is necessary in order for it to fit. Once traced I proceeded to use a 4" hand grinder fitted with a cut-off wheel in cutting the tunneling.