What are some of the most practical V8 conversions for the M37?

[Bill Kiene]

I have always loved the M37 and some day I might get one to completely work over.

Just curious what V8 motors are common or practical to install in one.

I have seen the diesels but am more interested in a gas motor.

I have seen a few Dodge 318 V8s which kind of makes sense.

Any auto trans conversions?


**50 years ago I saw a 2 1/2 ton with a Dodge 383 and I think a 737 auto trans.


Thanks......

 

[Gunnermac]

We just finished installing a small block chevy (350) in a M43 ambulance,makes a very different truck. I would suggest changing out the ring and pinion to get a higher final ratio. We considered a 318 but had the 350 so we used that.

Mac

 

[zak]

Bought this m43 with a small block and auto trans. Had a very short driveshaft. Gas tank wasn't hooked up only gallon can. It had very minimal rust in the usual spots so it was a perfect candidate to restore. Since I'm not one to stray from originality, I pulled the engine/trans and gave it to a friend. But as you can see it fit, the transfer case and radiator were in the stock place.

 

[Bill Kiene]

A really interesting V8 motor might be the smallest old Chrysler Hemi, the Dodge Red Ram?

https://www.hemmings.com/magazine/hmn/2013/10/Dodge-Red-Ram-Hemi/3730921.html

 

[nattieleather]

A GM 6.2 or 6.5 diesel with TH400 or 700r4 transmission fit nicely into the m37. If you add a turbo then you have to modify the engine bay for it to fit.

 

[Tanner]

A GM 6.2 or 6.5 with a Deuce 3053A Spicer trans -

Tanner

 

[JimC2]

I'm a little late to this thread, but back in the late 1960s I installed a 318 in my 37, retaining the NP 420 in stock location so the PTO position would remain unaltered. A couple of years later I installed a big block Chevy and SM465, again retaining the PTO location. Both were simple, quick installations.

 

[JimC2]

I'm thinking about doing a Dodge 360 Magnum Stroker swap (410 c.i.), again hanging with the NP420 and keeping the PTO in stock location.
Anyone done this one before?
Any tips?

 

[ab705]

I'm thinking about doing a Dodge 360 Magnum Stroker swap (410 c.i.), again hanging with the NP420 and keeping the PTO in stock location.
Anyone done this one before?
Any tips?

If you're going to install a big mill, you might consider getting a set of high-strength rear axle shafts. Both of my rear shafts had a very noticeable, sharp twist right at the end of the splines at the differential end of the shaft where the change in cross-sectional area creates a stress riser point. And that was with the stock six-banger. I looked at several used axle sets, all of which had at least one shaft that was twisted to varying degrees. I ended up getting a pair of NOS shafts. I suspect that some previous owner accidentally popped the clutch when it was sitting on dry pavement, or something like that. I think I still have the old shafts. If I can find them I'll take a picture of the twist. Maybe this was a problem that was corrected later, but you might want to research it a bit.

 

[JimC2]

Thanks for the tip. I've had a big block Chevy in my 37 for over fifty years. About 375 hp and a fair amount of torque. No problem with broken axles. You just have to pay attention to when and how you apply throttle and clutch.

 

[ab705]

Thanks for the tip. I've had a big block Chevy in my 37 for over fifty years. About 375 hp and a fair amount of torque. No problem with broken axles. You just have to pay attention to when and how you apply throttle and clutch.

You're welcome.

My axles weren't broken...just twisted...but it made me question the metallurgy involved in their manufacture, and made me wonder if the next unintentional over-stress situation might be enough to break them. I see that VPW is selling a pair of hardened 4340 steel 2-piece (shaft and cap) rear axle sets, but they're not giving them away. As you said, I just plan to be careful about how I apply power, as well as being careful not to pull too hard when on a paved surface, etc.

 

[JimC2]

I can snap an axle at will on pretty much any surface just by cobbing the throttle. I choose not to do so.
I'm not knocking the stronger axles; they are a good thing, but they can be broken too. One thing I've learned not to do is give full throttle in reverse when in a tight left turn. The left front axle doesn't like that.

 

[ab705]

Yes, I agree than any axle can be broken if circumstances allow you to apply enough torque to it.

The axle shaft isn't always the weak link in the chain. It's possible that with the high-strength axles, something else might break first.

I had an old British Land Rover many years ago, and on one occasion I was trying to be helpful and pull out a truck that was stuck just off the side of the road. I was on dry pavement and pulling in low range in 4WD, which wasn't a smart thing to do, considering how deeply mired the truck was, and the Land Rover didn't like that at all. Instead of breaking an axle, it snapped the spider gear shaft in the rear end. Fortunately, it had a full-floating rear axle, so I was able to pull out the axle shafts, disconnect the rear driveline, and drive it 400 miles to Phoenix, plus another 660 miles from Phoenix to Salt Lake...using the front axle only.