g741.org

MM - the "doohickie" is actually a coil-spring wrapped, airbag auxiliary spring that the previous owner had jury rigged to help support a gin-pole setup. Needless to say, they are not there anymore, infact, none of what is seen in the photo is there anymore, other than the body and frame...

JimC wrote:I've thought about the TSL boggers. They are great tires, but 38.5 isn't really tall enough to cut down to our average hardpan depth.

And they will cut big ruts in a hurry too! IMS, the Super Swamper SX is available in a 41x13.50x...

I seem to recall that when I was fitting my truck for the 44's, I also had issues with the rear tire fitment as well, as I found the rear fender wells to be rather shallow in its depth to accommodate a wide tire and the huge offset of either the factory wheels, or the stock H1 wheels that I was trying to make work. With my GM 14 bolt rear end being only 67" wide I had to run a 3" spacer to make the H1 wheels work, and I'm sure the tires would have rubbed on the inner fender well as the suspension moved. I wasn't planning on recentering them at the time though...

The mud up here is either bottomless, or its only about 8" deep with the consistency of axle grease (wet clay is really slippery!) and its usually found on everything but flat ground. Swampers seem to work best, but we've managed to clog them up to look like drag slicks as well. I've been really impressed with the Michelins, but I've got lockers in both diffs and lots of HP to turn them, so that works to my advantage.

I've got an old KS-22 Detroit Automotive No-Spin in my rear, but nothing in the front. I have an extra KS-22 I may put up there, to join the Warn M-13's. What engine and transmission are you running? I'm using an SM-465.

Lots of speculations, not much actual data.

I ran Goat wheel/tires for over 100K on my Diesel M37 starting around 1985. I already had an air-over hydraulic brake system from the deuce, so whatever boost was necessary wasn't a problem. The front axle was raised 2" for the 3-53N Detroit to fit.

They fit without much work, had to trim a bit of the bottom left splash pan off. No problems during some really tough off-road conditions. I never had power steering on it.

They are a steel-belted BIAS tire, mostly made by Goodyear. Remarkably in balance without weights at 65 mph. Not so easy to find today. Typical tread life was around 6,000 to 7,000 miles with rotation. (I bought them by the dozen, cheap back then)

The OD from the bigger circumference was a blessing on the highway for top speed, off road for the much improved 'roll over the cracks' size.

Dennis aka PoW.

Jim, I'm running a '69 428CJ on propane, coupled to an NP435, and currently running a married Dana20 tcase into a divorced NP205. The whole build up of my truck is posted here: http://www.g741.org/PHPBB/viewtopic.php?f=10&t=2420
The trans and dual tcase setup will be coming out hopefully this winter in favor of a rebuilt NP435, backed by DNE2 aux. overdrive and a married NP205.

Thanks for the observation Dennis, although in most circles, pictures, web links, and measurements are usually considered to be more factual than speculation. Where I am, gama goat wheels are about as common as Unicorns, so there isn't much point in researching something that is unattainable. However, I'm willing to learn more about the swap, so please include some additional data on how you managed to do it 30 years ago, and how its still a relevant swap today.

I think I'm gonna derivet the centers from some of my junk 37 rims and weld them into new 17 or 18 inch reversed hoops. Get rid of the split rings while sort of keeping a hint of the M37 look to the wheels. I'll draw it up in Autocad first to help define backspacing and how much the M37 centers have to be machined down to fit the new hoops.

Ain't it nice having both adequate power and rpm capability
Did you have to do anything to your engine compartment to get the 428 to fit?

I didn't have to mod the compartment with the BBC, but I did slightly cock the bottom of the engine toward the driver's side so the oil pan would clear the front pumpkin with a slight dimple in the pan for extra clearance, and I left the top of the radiator in the stock position but cocked the bottom forward a couple of inches to clear the fan. I use a hydraulic clutch on the GMC bell housing, powered by a Plymouth brake master cylinder mounted backwards beside the M37 brake master cylinder. I have an extension arm on the bottom of my clutch pedal pivot to reverse the direction of pushrod travel to push the Plymouth cylinder. Nothing special about the choice of Plymouth cylinder -- it was just what was lying around the shop when I did the conversion. Biggest effort in the conversion was positioning everything so the PTO jackshaft would still fit the stock jackshaft frameholes.

Only thing I don't like about my setup is the cathedral bowl Holley. Because of the cathedral bowls, the truck doesn't like to run diagonally across cotton or cornrows at speed -- the fuel starts sloshing within the bowls and fuel supply gets a bit spastic, developing a stutter. Doesn't do it under any other circumstance. The glitch has made me consider throttle body injection, but I haven't taken the plunge yet. Time has come to rebuild the truck, so may push me into it.

I didn't really have to do anything to the engine compartment to make the 428 fit; the biggest headache I had was the exhaust manifold on the passenger side flares outward a the rear to dump the gasses. With the aftermarket support for the FE engines being what it is, I was fairly limited financially with what I could do to remedy the problem of the engine sitting too high in the chassis due to the manifold design. The easiest solution for me was a 2" body lift, solved all the fitment issues in one shot.

I too run a hydraulic clutch, only I'm using a GM external slave cyl. on a custom mount and a Willwood master up on the fire wall. I converted over to hanging pedals using a kit from Heli-Tool designed for a civilian Power Wagon to push the plungers for both the clutch and brake masters.

You're absolutely right about how nice it is to have both power and RPM to play with. I'm lucky enough to not have any fueling issues, as I converted the 428 over to Propane. Around here the propane has an octane rating of about 108, which allowed me to take advantage of the 11:1 compression ratio and put about 30* of timing back into the engine. Plus its about $2 bucks a gallon cheaper than gasoline, so its really the only way to afford to run a big block anymore.

Stockton Wheel in California used to offer tubeless wheel "hoops" for custom centers, but I've heard they went out of business. I've seen other M37 owners get nice wheels from Marsh Racing Wheels as well. Anything you want is available, its just determined by the budget that's pushing the project...right?

I've never bothered to budget anything, but I do find it diffcult to keep my planes, cars, and trucks all running at the same time.

Stockton is back in business. Lead time for a set of 17" hoops on my M37 centers is a month or two. Interco is working with me on determining appropriate backspacing for 17" reversed hoops (17" chosen solely to keep as much of the 37 centers as I can). I'm trying to find the dimensions of the 17" hoop contour so I can draw the rims up in AutoCad. I'm going to go with the 42" Iroks, though I wish they weren't so wide. I'm not convinced yet that the hoop reversal will be necessary.

I use a GM external slave bolted directly to the GM bellhousing (I run an SM 465 transmission). Pedals are stock with a clutch pedal lower extension to reverse the direction of pushrod travel. I was able to find a set of cast iron truck exhausts that had adequate flow while still hugging the block closely enough to fit between the frame rails. I'm at the point of replacing the engine again and am wondering if I can get a tall block to fit. If I can, I'll probably go 540 c.i. instead of 502.

Truck gets about 11 mpg on the road, but is a fuel hog off. Cheaper to run than the airplanes though.

Yota:

I never even insinuated it would be practical to use the goat wheel/tire combo today. It was mentioned as an archival experience log.

They have (unfortunately) faded from the landscape, being a one-off setup just for the Gama project.

At the time, many goats went into the chopper for the metal, and huge mounds of tires & wheels were available in Utah @ $40/per. Most were unused tires.

Some 18's available today are useable on goat wheels, but run over $300 each and are not really practical. The wheels themselves (by Sankey of England) mostly went into scrap as the rubber dried up in the early 2000's.

I believe there are some pix I posted in the gallery showing what it looks like up close.

I still run them on my stock M37, and have but one set stashed for later. I sure don't drive it as much as I once did, as the Diesel rig was sold a few years back.

PoW

Fair enough PoW.

Jim, another thought that occurred to me would be to look into a weld-on bead lock kit for the original wheel to replace the lock ring. I have no idea if it would work or not, I have no way to make a comparison. Its just a "spit-balling" sort of idea... Most of the weld on kits for regular tubeless wheels will add about an inch to the width, something the stock wheels could do with.

If you are considering a 540ci. stroker, you may be at that point to consider some additional drivetrain strength. If that's too much work, I believe that Foote Axle - http://www.footeaxle.com/pages/home.php has offered new M37 axle shafts in modern alloys. They may even be able to make them in chromoly.

That's interesting about the bead-locks. I don't know much about them, but will look into it. Because of our local terrain I've never had much trouble with bead slippage because I've never needed to increase flotation by means of low pressure. Which translates to my being ignorant about bead locks. I have had a lot of trouble with bead slippage when operating my planes in sand though. Also when doing hard braking on solid surfaces.

I didn't realize that Foote had run off a new batch of axles. I've never had much trouble with drive train breakage because I like the big engines for their off-peak torque rather than their maximum torque. In other words, I learned many years ago how much throttle I could get away with in different situations, and I've stayed off it when it would break something. On the other hand, I also learned not to loan the truck out because it would usually come back with something broken when I did. They would usually twist a driveshaft or either break the rear short axle (probably by popping the clutch), or a front axle by backing the truck up under load while in a right turn.