Even with the 3.23 gears from the factory? It would seem to make more sense to have a wide ratio in there with those.
It sure would be alot nicer to drive with a M-20 but buick may have put a M-21 in it. My 72 had 3.08 and a M-21 from the factory. You get good at feathering a clutch and then get better at changing the clutch. I havent had those gears in the car since 81.
It should of been a M20 Wide Ratio. 3.55 seems to be the GM cut off on the M20/M21-22 trans. Of course like the previous post says, odd things happen. That car might of been special orders with an M21, who knows. The "right" trans in a '68 is the M20 case #660, with a 1 inch counter shaft, 2.52 to 1 first gear. You could use the #1352 case 7/8" counter shaft trans, both will have the 10/27 input/output ends. The later #661 trans case used a 26/32 arrangement and required a different clutch disc & TH 400 style yoke. Easy way to do this using a 10/27 trans in place of the Powerglide. I did this swap a while back using mostly all stock parts in my '69. You will run into troubles locating a flywheel & bell crank (z-bar). I did a lot of cross reference in the old GM parts books to determine what interchanged between the models. Here is what I found: Z-bar - Chevelle w/SBC or I6, Skylark w/SBB or I6 Flywheel - Skylark w/SBB, 350 cu in or Jeep '73 model year w/SBB 350 cu in Trans - Muncie M20 - Camaro, Olds, Chevelle, GTO, Skylark 1967 1/2 - 1970 early. Yoke - TH 350 or Powerglide, bonus, used the same driveshaft! Shift linkage - GTO Super Comp Hurst, repop linkage from Year 1 Pedels - Buick specific, but parts book said 71 & 72 Pontiac with SBP works (it did) Clutch rod - Buick specific, I used a Chevelle unit & it worked Z-bar frame tab - any A Body will work (or repop unit) bolts in place Ball Stud for the block - used a Camaro unit Hope this helps, Jim
70 chevelle could be ordered with an m20 or an m21 - 350v8 (4bbl) or 396v8. i remember reading the option sheet.
All factory stage1s (except a very early '70 with an M20) I'm aware of came with an M21 I have 3.42:1 gears I've never seen any proof of an M22 in a Buick. http://www.v8buick.com/showthread.php?t=74195
Marco is correct all Buick received M21's. GS-Jimmy you are also correct for Pontiac only, GTO's, GP's and Birds received M20's with 3.55 or taller gear .M21 with 3.90 4.33 axles. Not sure about Chev and Olds.
