Would some of parts on the list work? What is the most common brakes on the GTP tranny.

Yah, I saw that.... I also noticed that they list it as a Torsen Diff, which is already available at a premium price... I was hoping GM would have their own version.

Wait..... now that I think about it.... the final drive gear ratio doesn't have anything to do with the differential... If I'm wrong, please correct me, but the only variable that I know affected by the components on the differential is the speed sensor.

I e-mail the address on the PDF file. Gmsportcompac replied when I asked them if we could use any of these parts.

"The automatic transmission that we use in our drag racing program is from the Pontiac Grand Prix. It is the 4T65 Hydra-matic. There are two ratios in production, and we offer a streetable upgrade to one of them: 35/35. This is a set with upgraded gears and a single, wider chain (there are two thin chains in production - - for reduced noise). The price is $725.

We also offer a 3.29 torsen differential ($1295) and a 3rd gear clutch pack ($35). I don't know if you really need those or not. Quiafe also offers an aftermarket diff.

These parts can be purchased directly from GM Racing only. They require pre-payment by certified check or money order. They are not covered under any vehicle warranty."

Your right as far as I know. Only gears and chain need to be swapped for new gears, not the diff. But damn, 4.0 would make for some fast acceleration.

And do bupkis on for the top end. I'd bet if you put that gear ratio in the GP that you'd top out in MPH well before the end of the track essentially killing your ETs.

As for the quaife those things have been on back order for years now.

i would still love to see a manual trans for the gtp...that would definately make me smile a bit...

I could suffice with paddle shifters for fun. Being auto, with our ability to play with the pcm, is perfect for dragging.

1000 hp?

I dunno...