[Cobra 29]

I agree with Jimi and JWD. I have 26" tires and 3.21 rear gear and the TKO600RR (with .82 OD) is perfect. My first gear is much more usable because the car launches well and I do not have to shift into second so quickly. The .82 OD works much better than the previous 3550 with the .64 OD; my engine stays at 2500 to 2700 at 70 MPH. Previously, the engine's RPM was too low about 1800 RPM. I switched from a Tremec 3550 to the TKO600RR. I purchased the transmission and advice from Jimi at Standard.