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The M37 I'm getting is 12V, I want to put electronic ignition in it like another car I have. What is the best option in this case? I saw something but it was listed for a 24V system. I'm not very good with electrical but I wanted to point my friend the mechanic in the right direction since they are not used to these trucks.

On the other matter, is the 4.89 gearing swap really a great thing to do, opinions? I will be driving on roads more often. I don't have anyone to ask these questions!

Thanks

my truck, recently rebuilt end to end, has the original gears. Where I live, I can get to anywhere by the "back roads", and have no plans on venturing out on the Interstates. My truck has plenty of power whenever I ask for it. I read that the transfer case can get hot at higher speeds, and even though my M37 tracks straight and true down the road, I am quite content to cruise around at 35-40 mph. And I like the ability to use the torque of third gear at low rpm to avoid having to double clutch down to first, which I can do easily. I keep an eye on my rearview mirror, and if cars behind me come up, I just ease onto the shoulder or a turn lane, and slow down to let them zip around me. With the big tires, running in the grass is easy. I do have some 200 mile trips coming up, but I will just take my time and enjoy rural Upstate SC. The torque multiplication of the OEM gears is just perfect for me. I sold a Porsche GT3 with around 430+ horsepower to get my truck, and had a 427 Cobra before that, so the relaxed pace of my M37 suites me just fine.

NAM VET

Yeah I obviously plan to take my time in it haha, I am near the coast and will probably cruise to the beach to surf with it. I am in the North Bay near SF, so Tahoe is a bit far and I thought about Death Valley but that seems pretty far at that speed as well. There are a few dirt road trails north of us here I could try out. I have an old diesel Mercedes so I am used to dealing with a different power band than the modern cars all around me. I'll try it out and see how it goes. I'd like to keep it original. I just finished a 240Z a year or so ago, that is the speedy ride. Thanks.

Jarhead

From what I remember, 4.89's will give great top end, albeit a tad expensive, my memory ain't what it used to be. Along with more power/speed, you'll need better stopping power, disk on the front at least, this is just my opinion? The Pertronix is a good upgrade, one I am hoping to implement, like you I am 12 volts and not sure what the part # is.

I'm in Oakland and have tried both. You're welcome to take my M for a spin and decide .

Andy

I'd take Andy up on his offer! I got to "take a spin" in Andy's M37 with the 4.89s and the difference is noticeable immediately! However, like Nam Vet, I'm in no hurry to get around-35-45 mph is good enough for the short trips I take.

Send Charles aka m-series rebuild a PM for info on the Pertronix; Vintage Power Wagons also has them-make sure you have the model number of your distributor so you get the correct one.
Gary

ashyers wrote:I'm in Oakland and have tried both. You're welcome to take my M for a spin and decide .

Andy

Oh cool, I don't have the truck yet. It's going to go to my friend's shop in Petaluma for some paint and whatever else we can do, like seatbelts. Maybe when I get it on the road you could come to cars and coffee in Marin for double M37 action. There is a long straight road around the Vintage Oaks shopping center that would be good for a test. I'm right in the middle of Greenbrae, Larkspur, Corte Madera.

You'll want to go to this:

http://www.g741.org/PHPBB/viewtopic.php?f=6&t=8544

You'll see a few M37's and a ton of other goodies. If you need any help on the M feel free to give me a shout, I'll PM my #. I've learned a few things since I picked mine up 3 years and 10K miles ago. They are fun trucks!

Andy

I recently drove my 1962 M37B1 just over 5200 miles from Green Bay, WI to Santa Monica, CA and back while pulling a M101A1 trailer. The truck is all original, except for front lockouts.

I was in the 3/4 ton march unit of the MVPA Route 66 Convoy.

Before the trip, I changed out the third member to a 4.89 rear end. I left the front with the original 5.83 gears. The front has lockouts and is not used.

The 4.89s worked well giving a comfortable cruising speed of 52 mph while on the interstate coming back.

Going up mountain passes, and pulling the trailer, was not a problem as long as you didn’t want to do it fast.

If you are going to do convoying or travel distance I highly recommend the 4.89 conversion.

BTW: The M37 had no mechanical issues the entire trip. It did suffer two flat tires due to pinched tubes. I have learned to slather things up with Murphy’s Oil Soap and inspect the flaps for high spots at the seam.

I wouldn't use Murphy's on my tubes. I have had 50 years of great success with talc or baby powder. Lots of it. I always put a few pounds of air in then deflate completely. Then air it up. This helps get rid of any wrinkles.

Any kind of petroleum on a rubber tube is a bad idea since it will degrade the rubber. Talc like was said or dish soap but then you have moisture in there that can never escape. Same with the Murphy's, moisture that will be there for the life of the tire.

Bob Stahl from Veteran Vehicles has an outstanding article on 4.89 gearing for the M37.
He's a very helpful guy, sells parts (including an M37 third member with 4.89 gears installed), and knows these trucks!
Go to this site for his article.
https://www.dodgepowerwagon.com/stahl/gearing.htm

they are designed to go 55 with stock tires and 5.83s. its a bit noisy at that speed but will do it. I have at least 150K miles with 5.83s and usually run 50 to 55 on highway. the least expensive way and almost as effective is to go to taller tires. much easier and brings down rpms nicely. the tcase doesn't get too hot. I think some people fear that it will but it wont. why would it? I have never run petronix. I have read about them failing with very low miles in hot weather. and I have a dwell meter so my points last forever. pertonix in a car might be fine but these trucks are wound up pretty good and have lots of road vibrationsso maybe the petronix doesn't like the harsh environment?

I'd try it like it is for awhile first. See for yourself why it was designed as it was. Then, when you know what are actual issues as opposed to theoretical ones, change what you need to change. You will probably be surprised how different the fears are from reality.

-jim lee