Farmall M Conversation with GM-Detroit Diesel 3-71

Robert in KY · Jul 12, 2014

A buddy and I are thinking about putting a 3-71 GM/DD into a donor Farmall M. I know a 2-71 will fit and can be done. Has anyone seen or tried to do this before? Will it fit/work without completely modifying the frame of the M?
Let me know!

caseman-d · Jul 13, 2014

Not sure if the drive train will hold up on a M with a 371 in it.
casenan-d

Robert in KY · Jul 13, 2014

(quoted from post at 15:18:13 07/13/14) Not sure if the drive train will hold up on a M with a 371 in it.
casenan-d

Too much torque/horse power for it?
I'm assuming that the guys I see at shows and pulls running small block V8s are changing out the drive train altogether?
Never done an engine change on a tractor before so any advice is welcomed.
Not really sure what the tractor would be used for at this point. If I go the "pulling" direction we would put more into the type of pulling we are looking for I guess.
If we go the parade show route, I guess we have other options as well. Basically, this brings me back to the original question of can it be done at all? Will the engine even fit? Should I just stick to the 2-71?

Bob M · Jul 13, 2014

For a show/play tractor a 3-71 would be fine. But for a "working" M, a 3-71 repower has a high risk of tearing up the transmission/rear end. (Keep in mind he M rear end is designed for about 40 HP - a 3-71 easily delivers 120 HP.)

Not certain however whether there's sufficient frame length to shoehorn in a 3-71 (it probably can but it will be tight). The shorter 3-53 would be the better choice if you really want a 3 cylinder, Detroit-powered M.

Regarding pullers running small block V8's, these develop their power by running much higher RPM's. The torque delivered to the rear end may actually be not a whole lot more that of a stock engine. Further, a puller tractor transmission only to needs handle this for a few seconds during a pull.

Bud Kaiser · Jul 13, 2014

I know a guy who has a 5.9 cummins in his M .It
still has stock rear end and he has been pulling it
for 2 years now with no problems.

D Slater · Jul 13, 2014

Someone may have a picture of a 3-53 in a M or SM from a red power roundup. Think I remember a SM with one in Lebanon TN. Think the tractor frame was standard length without a lot of modification. Think I may have some pictures of other Detroit installations if I can find.

CenTex Farmall · Jul 13, 2014

If the bearings are in good shape the strength is there. Tractor pull is more of a test of ultimate strength as opposed to durability.

Tire slippage is a big factor. If you were to say put duals on it and 4 or 5 bottoms behind it then something will give.

The hot rod tractors always make with lots of wheel spinning and that helps the rear live.

Farmall M Conversation with GM-Detroit Diesel 3-71

Robert in KY

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caseman-d

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Robert in KY

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Bob M

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Bud Kaiser

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CenTex Farmall

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