Repower or not

[rush]

So I have lot's of time to think about my future M37 project, since Im stuck here in Irac for about another 6 month's. Originally I wanted to update to a little better performing engine perferably a slant six. A 4BT would be great but out of the question right now do to cost. However now I'm thinking twice about changing engines. The truck will normally be trailered to trail sites and will spend most of it's driving time below 25 mph wondering the mountain trails of the Cascades and central Oregon. This is my second M37, and I was not in a location to do any mountain trail riding with my first. I have allready purchased two sets of helitool brake kits, and would really like to get one of the ARB lockers while they are available. The truck will be getting power steering added also. So from the more experienced drivers of these trucks, more modern engine or not. Thanks

[MasterYota]

My own enjoyment leads to a repower with a newer engine. I would belive that wheeling in hilly country, with the threat of mud would necessitate an engine swap to something with more RPM capability. The lack of rpm band on the flathead is the real downfall, not its power output. I think you'd be quite happy with the Slant 6, or a small v8, whichever fits your budget or engine bay better.

The stock axles can be broken with the Flathead, so keep that in mind when coupled to your wheeling style when making an engine selection. If you're at all like me, you'll change your mind 15 ways from sunday untill you actually have parts on the floor, and tape measure in hand.

Good luck, and thanks for your service!

[rush]

My own enjoyment leads to a repower with a newer engine. I would belive that wheeling in hilly country, with the threat of mud would necessitate an engine swap to something with more RPM capability. The lack of rpm band on the flathead is the real downfall, not its power output. I think you'd be quite happy with the Slant 6, or a small v8, whichever fits your budget or engine bay better.

The stock axles can be broken with the Flathead, so keep that in mind when coupled to your wheeling style when making an engine selection. If you're at all like me, you'll change your mind 15 ways from sunday untill you actually have parts on the floor, and tape measure in hand.

Good luck, and thanks for your service!

Thanks for the input masteryota, I am still leaning toward the 225 slant six. The measuring tape and note pad will come into heavy play before a final decision is made. Normally mud is not my thing, tears up the area to much giving the eco nuts more ammo to shut us out of the driving areas, and is such a pain to clean up. I was thinking of a 283 chevy if I go v8 power. Small cubes = less tq = less breakage with still a vast improvement in rpm ability.

[Drew M.]

The stock 230 is awesome for rock crawling. It has lots of low rpm torque to pull through boulders at low speed unlike most V8's. I used mine at the Rausch Creek, PA SteelSoldiers.Com rally last year. it was mostly rock crawling - photos on the rally forum at SS.

I agree the 230 would not be good for slinging mud - based on it throwing rods and the broken axles should the tires suddenly get traction.

The 4bt would be a major improvement though - for the $$$.

[Gsmith]

Based on your description of intended usage I would think the stock 230 would be fine. Low speed and reasonable low end power is what you would be looking for. I don't take my mine off road, but just driving it around makes me think it would do just fine for trail riding.

[MasterYota]

Thanks for the input masteryota, I am still leaning toward the 225 slant six. The measuring tape and note pad will come into heavy play before a final decision is made. Normally mud is not my thing, tears up the area to much giving the eco nuts more ammo to shut us out of the driving areas, and is such a pain to clean up. I was thinking of a 283 chevy if I go v8 power. Small cubes = less tq = less breakage with still a vast improvement in rpm ability.

I wheeled my own M37 with the Flat 6 for a while, and the best upgrade from an engine repower, wasn't exactly from the engine, but the swap to a newer 4spd trans which was easier to shift. When wheeling in hilly country the ability to upshift or downshift faster can be a godsend. A good set of offroad tires will help alot as well, the NDT's are terrible.

The 230 6cyl makes about a 170 ftbs at 1200rpm. Any V8 will generate more torque, but, as pointed out, at a higher rpm. I ran a Gm 305 in mine, and never had any issues with breakage. Plus it was easier to come accross than the 283. If you still want a small displacement gm V8, consider the early 80's fullsize cars, they often had 267 v8's in them. They are cheap, easy to come by, and a newer Gm 2wd 4spd (SM465) bolts right up.

[Gsmith]

Being in Florida I'm not familiar with wheeling in hilly country, so I have to ask why it would be necessary to be able to shift faster than the stock transmission does.

Thanks, Glenn

[MasterYota]

Being in Florida I'm not familiar with wheeling in hilly country, so I have to ask why it would be necessary to be able to shift faster than the stock transmission does.

Thanks, Glenn

Up in BC, the hills are usually one of two things, steep, or long, or both. I found that M37's don't always have the best brakes, especially after they've become wet. Downshifting from 3rd to 2nd can sometimes mean making the corner at the bottom of the hill or not. Not having to double clutch a newer transmission can save precious seconds when caught unprepared with soggy brakes that don't do much for a 6000lb truck.

A faster shifting transmission also works well when mud is encountered. With a limited rpm band, and deep gearing, shifting the trans to gain wheel speed is needed to get the tires to clean out and foster forward movement. Sometimes its nice to upshift or downshift without losing momentum.

Everywhere is different though, that been my experience so far.

[MoparNorm]

First and foremost, Thank you for your service!

Secondly, go sit in the corner and wash your mouth out for mentioning SBC....ha! ha!

The most fun I ever had in an M37 was riding with Sam in "Jethro" (RIP Jethro!)
It was a 360 powered beast and a ton of fun. I would think that a stock 360 or built 318 Poly would give you all the torque the stock drivetrain could handle and work well with the mods you have planned.
I don't want to start a war here but the slant 6, although a wonderful, economy motor, would not be worth the effort in time or money.
If you're going to do it, do it so you can tell the difference.

[rush]

Sorry about the SBC thing, 318 would work great and is more avail. The slant six has been a thought for economy on fuel, higher rpm, fairly short overall length, and having a reputation for being bullet proof. There looks have even grown on me somewhat. Wierd! I have seen the truck "Jethro" in some other pics and even have one cut out and posted on my wall here. Way cool looking truck.

Thanks so far for the input from all of you. Looks kinda like of course the harder core wheelers want V8 power to get through those tuffer spots.

By the way you have (RIP Jethro), did it come to some demise?

grant

=MoparNorm;73141]First and foremost, Thank you for your service!

Secondly, go sit in the corner and wash your mouth out for mentioning SBC....ha! ha!

The most fun I ever had in an M37 was riding with Sam in "Jethro" (RIP Jethro!)
It was a 360 powered beast and a ton of fun. I would think that a stock 360 or built 318 Poly would give you all the torque the stock drivetrain could handle and work well with the mods you have planned.
I don't want to start a war here but the slant 6, although a wonderful, economy motor, would not be worth the effort in time or money.
If you're going to do it, do it so you can tell the difference.

[/QUOTE]

[rush]

Just out of curiosity how much better do the 251's in the ffpw's pull? And what kind of mods did the CDN M37's have to install the 2 inch longer motor?

[maineSS]

The 251 was rated at 115 hp- haven't seen any torque figures. The last years of civilian 230 production '59-60 saw the introduction of an 8:1 compression head with redesigned transfer/valve pockets that brought Hp up to 120 with the awful intake/exhaust system these engines have. The car users have improved output with dual carbs and split exhaust. When I rebuild my 230, it's getting the 8:1 head and triple Mikuni sidedraft snowmobile carbs, plus some valve work.

The stock slant six would give you about the same Hp/Tq at a higher rpm range. It was fitted in the Export M601 by Dodge, so it can be done. Access to the distributor would likely be difficult. The Slant can be modified to develop very respectable power levels for its displacement.

[MoparNorm]

...By the way you have (RIP Jethro), did it come to some demise?

grant

Sadly yes, it sustained a plethora of damage over the years to drive train, frame and body. Sam decided it was time to retire Jethro, a great truck!

[W_A_Watson_II]

Based on my start with "Franky" My M37 is likely to follow in Jethro's foot steps, but I hope not.

What was Jethro's undoing or the main failures?

[MoparNorm]

If I can recall correctly, it was frame failure.
Sam didn't baby Jethro, it was one fun ride, but succumbed to the rigors of the trail.
Early Jeep frames had the same issues before they started boxing the frame. Less flexibility traded for more longevity.

I had the privilege to see Jethro in action in both CA and TX.