SupDoc Posted March 25, 2023 Report Share Posted March 25, 2023 I recently acquired a L20B that I'm going to install in my 510. The 510 currently has a 5-speed 63A transmission mated to a L16. My understanding is that 63A was originally sold with the L20B. What modifications am I going to have to undo, in order to take it off the L16 and put it back on a L20? Quote Link to comment
datzenmike Posted March 25, 2023 Report Share Posted March 25, 2023 Nothing. The transmission will bolt right up to the L20B. Hopefully you have an L20B flywheel and a clutch assembly. You will need the correct release bearing collar to match the clutch/pressure plate you will be using on the L20B. The 63A was an option on the A series engine in the April '76 and on B-210 coupe. It was standard on the L20B in the '77-'79 S10 (200sx) and an optional 5 speed on the '78-'82 A10 on both the L20B and the Z20S series engines. Quote Link to comment
SupDoc Posted March 25, 2023 Author Report Share Posted March 25, 2023 I actually have the entire drivetrain from a 1980 720, so I should be able to take the flywheel and clutch from that. The only reason I'm not considering using the 5-speed from the 720 is because it's the longer 31.5" version, so I'd have to shorten my driveshaft to make it work. I also just paid a lot of money to rebuild the 63A. Quote Link to comment
datzenmike Posted March 25, 2023 Report Share Posted March 25, 2023 Keep the release collar with the clutch from the '80. But get a new release bearing or three months down the road it will start squealing. Not a fan of the 63A, it's ok but awkward 1-2 shift the most common. Quote Link to comment
SupDoc Posted March 25, 2023 Author Report Share Posted March 25, 2023 Thanks for the advice. Do you happen to know if the longer 720 transmission will fit in the 510? Would the shifter arm come up through the tunnel in the same location, or would that have to be modified as well? I'm actually not opposed to using the 720 transmission, if it's much better than the 63A. One thing I liked about the 720 transmission is that it seemed to have a higher 5th gear than the 63A. The truck didn't have a tachometer, but it was much quieter and sounded like it was revving lower in 5th gear. Quote Link to comment
datzenmike Posted March 25, 2023 Report Share Posted March 25, 2023 My 710 had the 26" 4 speed practically identical to the 510. I put a 280zx 5 speed in and did not need to trim the hole in the floor though I did use a later 720 shifter that has a small bend in it. It clears in every gear. The 63A in the S10 has a 0.854 OD or a 14.6% The 71B from a 2wd '80 720 has a 0.882 OD or a 11.8% This is a wide ratio transmission for use in a loaded truck. OD can't be too high a jump from 4th or it will struggle on the highway. 510 and 720 are apples and oranges comparison. Transmission may just have been quieter, more sound deadening under 720 carpet. 1 Quote Link to comment
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