4.0 Head on a 232

68AMC770wagon -- you're mistaken on the model number. The "3" in 35 is just the model number, not the number of forward gears. All "3" series are air cooled. AMC used a 35 and a 37. 35 was used behind 196 and 199, 37 behind the 232. They are almost the same, but the 37 will take a bit more power. The second number is the power level, but there's no correlation to a level -- the bigger number is just stronger than the smaller one. AMC also used a model 4x series behind sixes and small V-8s and the M-11/11b/12 behind the larger V-8. All are three speeds.


Edited by farna - Oct/03/2009 at 6:45am

The year and model, along with the engine, will tell what the car SHOULD have in it. I can look that up in the TSM.  But if the transmission has been changed, and it's possible on so old a car, the only way is to crawl under it and find the ID plate. It's on the driver's side of the auto trans. The model is cast into the side on the manual transmissions.

Your 66 Ambassador with 232 may have an M-35, but most likely has an M-37. The 66 TSM doesn't give the model number, that didn't start until 1967. Before 67 the V-8s had one transmission an the six another, and that's all the TSM tells you. For 68 there were three different transmissions, one for the six, two (new models) for the V-8s. There is an hexagonal plate on the driver's side of the M-3x series transmission. On the bottom left corner of the plate will be a screen printed number such as "No. AS2-35". The last two numbers are the model number. I don't know if you have a 35 and the 37 was new in 1967, or if you have a 37 as that was the 232 automatic in 66. There is little difference between the 35 and 37. The 37 has an extra tube inside and an external cooler can be added, and it will take a little more power than the 35.


Edited by farna - Oct/03/2009 at 9:04pm

You had a later model T-14, obviously. Try that with a T-96 and you'd be picking pieces up along the track!! Well, not that bad, but the synchro (only one between 2nd and 3rd) would have been toast. The T-96 was just fine behind the old 196, but anything more and it's marginal at best!! The last T-96 was used in 72. 

Forest is talking about three speed MANUAL transmissions. The 66 232 used a Y-86, which should be strong enough. The M-35 or M-37 AUTOMATIC transmission is a different story. If you have an M-35 it is fine for normal driving even with a mildly improved 232. A small 4V and little bigger cam, perhaps, but that's all. I wouldn't do much more than that in front of an M-37 either, but it should hold up better with the external cooler added. That was mainly added for towing, not for more power.

I think you would need an M-40 from a 67-69 290 V-8 or the M-42/43/44 from a 70-71 six cylinder or V-8 for reliability with a small blower or turbo charger. AMC dropped the air cooled M-3x series after 69, replacing it with the M-4x. 199 got the M-42, 232 (and 71 258) got the M-43, 304 got the M-44.

The M-4x is close enough to the M-3x that the output shaft housing from an M-3x should bolt on, and the length should be the same. Easy enough to convert one to the torque tube, as I'm pretty sure the spines on the output shaft are the same also.  I have to say that I haven't actually done this conversion, so some caution is in order. The only way to verify they are identical as I am reasonably certain they are is to find an M-4x series transmission and compare. I do believe that someone in the past has done this conversion (M-4x in place of M-3x on a torque tube car), but I can't recall who or when. So proceed with the knowledge that there may be a problem with something like the splines on the output shaft. That would be easy enough to take care of, but you would have to have the driveshaft from the M-4x car also. The M-4x may have used a larger U-joint than the M-3x did, but that is probably the case on all 232 cars as well. My only direct experience with the M-3x series is behind a 196, which doesn't need a big u-joint. 

No one knows EVERYTHING about AMC and mixing and matching parts... I do try, but can't remember it all!!  Not trying to be arrogant, I really do try to remember the more common or questioned swaps, and make notes on things that I find when possible. I have a full set of TSMs and use them. I've lost a lot of notes through computer failures (usually hard drive...), but try to make backups more often now!! Which reminds me.... I'm due for that!!


Edited by farna - Oct/04/2009 at 9:48am

I've messed with the older cars more than newer, they are a bit trickier sometimes and need more improvement in some areas... some were real "grandma" cars!!! Mostly they were built when roads were rough and you couldn't run fast for very long. Most of us don't remember when there wasn't an Interstate and pretty good roads, except for some really rural areas, and they are better than the dirt roads of the 40s and 50s! I STILL live on a dirt road, and we have quite a few out where I'm at, but even they have been improved to the point that they are better than they ever have been for sure!!