I have talked to Keisler's and was told the shifter has been relocated with their custom tailhousing to the first gen Camaro location and assured me there will be no cutting of the car's sheet metal plus they added a cable drive for the speedometer. The T56 with the 2.66 first gear and the double overdrives interests me because my car has the original 4.56 rear gears and a high RPM power range 302 engine. I feel the TKO600 .64 OD is too large of a gap between 4th and 5th gear and the 2.87 first gear is way too low for my 4.56 rear. I would have a "dead zone" between about 40 and 52 MPH in which 4th spins the engine too fast, and 5th spins the engine too slow. The 302 wants no less than ~ 2,000 for cruising. The T56 fifth gear is .74 OD and not as wide a gap from 4th gear and the .50 6th gear would be used for interstate driving. Where I live I would have to drive about an hour just to find a road with speed limits greater than 55 MPH so a lot of my driving will be at the 45 to 55 MPH speeds. I really wish either transmission had a closer ratio with a first gear of the 2.40 range.
Also under consideration is the TKO600 with 2.87 1st gear and .82 5th gear OD and change out the rear gear to 3.73 or 3.90. In the end the total cost for either the T56 or TKO600 plus new rear gears is similar and in the end I feel the T56 gives me a wider range of usable gears.
For the record I presently I have a M21 Muncie 4-speed with 2.20 first gear and no overdrive. My first gear ratio of 10.03 (4.56 x 2.20) seems to work well.
I too have a Z/28 Camaro (1968) with a factory 4.56 and Muncie close ratio. The car is great fun to drive, but is very limited on how far & fast you can go - 4100 RPM @ 75 MPH with 28" tires. I'm researching three different type of over drive transmissions, but not one is perfect to my needs.
1- The Gear Vendor Overdrive would retain close ratio gear spacing, but only reduce my RPM's by @ 75 by 900 RPM to 3200. 4th OD will work fine for the 50-65 MPH range.
2- TKO-600 with a perfect fit while retaining mech clutch/speedo, but again has a very deep 1st gear, no means to reduce RPMs between 50 - 65 MPH.
3- T-56 with 2.66 1st gear, that will fit the original shifter hole, retain mech clutch/mech speedo would be the optimum. I would probably cut new shifter hole in the tunnel if it did not break into the orginal shifter opening and boot mounting ring.
All three have a great produce, but which is the right choice for our application?
Also, Rockland Standard Gear (WWW.rsgear.com
) can provide a LS-1 T-56 with a special 5th & 6th ratio which would eliminate the problem of .5 6th gear. The new ratio's would be .8 in 5th and .62 in 6th. Talk with George Kreppen in tech services for more details. The price is $3995 (a bit pricely) but I want to buy the right transmission the first time.
Best of luck.
It's hard to explain and most people can't understand as they have never driven a 302 Z/28. The quick, high reving small block is alot more fun than major torque monsters. To each their own.