Gunfreak25

Acquired this old girl about a month and a half ago. Done lots of work and it looks so much better now since taking this picture. The truck was repowered with a 1971 Olds 455 and Th400 out of an old Delta 88 about 20 years ago.





Yeah! Very dirty, but that is an old picture. Here's the poop on the motor:

The prev owner has put new plugs in, changed all fluids and new points. You can see it had an old early Qjet on it, the only thing that has changed from the picture is it now has a 1976 carb off a 400 Pontiac. He said the old Qjet (pictured) was FUBAR. He said the Pontiac carb ran great. Upon delivery of my toy, I found it was difficult to start and WOULD NOT IDLE AT ALL for more than 2 seconds. It would just die as if someone turned the key off. You had to really keep on the pedal to keep it running. Once I had in the yard I began checking things out and tinkering around. First thing I did was change the filter on the inlet port of the carb, new fuel lines and inline filter. I also used an entire can of carb cleaner to get the carb cleaned up inside and out. After all this I had the truck running much better, but it was still really rough and had a really abnormal chug to it at idle. Of course, running manifolds only doesn't help. It's so loud I can hardly tell what's normal sounding and what isn't. A week went by of thinking what the problem could be. I was pretty sure it was running really lean or alteast a little lean. It was also heating up really quick after just a minute which would be a lean issue. Sure enough the next day when I had it idling (sort of) I stuck my thumb over a threaded hole on top of the intake. It sucked it down real quick, idle smoothed out tremendously and that odd chug was gone. I plugged the hole with a bolt and called it a day. A freeze plug decided to give out on me and it took me 2 days to get it out and replaced. For some reason though, after this 2 days it became very hard to start again and idled like garbage. I suspected more vacuum leaks as it was back to running hot after 2 minutes of idle. Sure enough, I found and replaced 2 vacuum lines at the rear of the intake that were rotted and cracked. It started right up but that odd chug was back and it still idled rough. Felt like I was chasing my own tail by now! I sat there for a little while before noticing the choke was opening almost fully after just a few seconds of idle. With the choke shut, it idles beautifully! I took a glance at the choke stove plate and it was set a full half turn PAST the 'lean" mark on the cover. I turned it back to the middle notch and the truck fired right up and idled quietly and smoothly for about 10 minutes. And that's about where I am right now. I need to replace my top radiator hose and get a small hairline crack ontop of the radiator tank fixed before I fire it up again. Next step is to pull the carb and attempt to rebuild it. I also need to get my dwell meter and timing light out to get things dialed in better.

If you guys have any suggestions though I would be happy to hear them!
I checked a few plugs and they look normal, motor sounds great and I bet I will get many years of use out of it!

svnt442

Now that's a neat toy!! Any clue as to how well it motivates with that pig in there? That's a bit more heft than it was designed to move ya know.

Rickman48

That should be a real 'stump puller' with all that torque!!
Final drive gears in that thing were around 9 to 1, as top end was about 60 MPH!

Sounds like you're starting out the right way, but I'd be checking the timing chain very soon, as those 'plastic' teeth on the top gear are notorious for 'going away'.
Pull the cap and watch the rotor, while turning the motor both ways with the balancer bolt - if there's more than an inch play, it's replacement time, along with the water pump!
Prevents bending valves if it jumps while driving.

Check the primary throttle shaft on that carb - frequently wear out causing another vacuum leak!
Have fun!

Gunfreak25

Just for comparison. The original G749 powerplant was a 302 I6 gas engine with a 4 speed 303M Hydramatic. Low range was a reduction cone on the rear of the Hydramatic and when engaged would bring the final gearing down to a jaw dropping 16:1 ratio! Top speed was 58MPH although getting there took forever and a day. With the tranny/engine swap I no longer have low range. However the 455 produces enough power to easily offset that problem. Still has the original 1 speed Tcase. "IN" for driving or "OUT" for operating a winch or other auxiliary equipment. It's a Sprag type Tcase, so engagement of the front axle for full 6x6 traction is automatic. It's very simple really, the Tcase is geared to spin the rear axles faster than the front.
So under normal driving conditions your powered by your rears only. If you go offroad or hit mud and the rears begin slipping (little as 2%) then this causes the Sprag teeth in the Tcase to rotate, causing the front axle to engage. Soon as you gained traction it would disengage again. I may de-spline my front axle hubs though. Lockers are very rare and expensive and if I de-splined them that would give me a real boost in tire life and gas mileage.

As for power, I have not driven it much yet but my friend has the same setup in the same truck and he smoked all 10 tires at Mcdonalds. He said it moves really quick but because of the weight your limited to about 60MPH unless you put larger tires on.

Thanks for the info, I will check out the rotor play today! How difficult is it to change a timing chain? The entire front end bolts off this truck so maintenance is a BREEZE. Floor plate comes out very easily, gives you access to your tranny and distributor shaft too!

Gunfreak25

I checked the timing chain. Marked the harmonic balancer with a pencil and it has 1 1/8" of play. Noticed there's a squeaking noise coming from the water pump/fan area when the motor is at idle sometimes. Could this be it? Does it need immediate attention?

Gunfreak25

My truck was made in 1954. The original engine was GM's gas 302 I6. On other forums we refer to them as "gassers" as many Military Vehicles made before the 60's were still using gas engines. Only Military vehicle I know of that uses the Mack engine is the M123 10 Ton Mack and it too is a gasser.
You might want to see if some guys on the Steel Soldiers forum have the parts you are looking for. Dodge M37 parts are still pretty easy to find. The M43 Ambulances are getting hard to find though!

Gunfreak25

I have a few simple questions for you guys! I pulled the carb last night and am getting ready to rebuild it with a $30 kit I found online for this carbs serial #.

1. This is a 76 Carb off a 400 Pontiac, will it work with my 71 455 Olds? Will I need larger jets and if so, part #?
2. While idling I noticed the carb/intake makes a pretty audible hissing noise.
Sounds like it's coming from the accelerator pump thing?
3. In the picture above, what is that large bracket on the front left of my block?

I appreciate the help guys!

Yellowstatue

It looks like your motor originally had AC and the bracket on the right is where the alternator should be... the left bracket looks home made...thats where the AC compressor would be mounted...

Texas Jim

I got my military drivers license @ Ft. Bragg, N.C. driving a gas powered "deuce and a half." Had to re-test, five minutes after the first test, as I up-shifted (a good clean shift), as needed, but did it before I got out of the intersection. LOL. They wanted you to keep it in the same gear you started off in, I think it was second as that thing was geared low even in high range, until you cleared the intersection. We just drove around on back roads w/ a bunch of guys in the back of the truck, and one by one, each guy tested and passed the driving test. LOL. That really is how it went back then. The "deuce and a half" was the "BEST" vehicle getting through the sand on the drop zones. In all wheel drive and low range, and full of paratroopers, you could keep the gas pedal on the floor and it would buck, and I mean buck, right through the deep sand. The jeeps would get stuck, and the gama-goats didn't carry enough guys. Yes, still the jeeps back then and they were starting to swap out the gas engine "deuce and a halfs" f/ the diesel engine jobs. Those were hard-core trucks, all metal and rock freakin' hard.LOL. Remember the vacuum operated windshield wipers, that would go like hell the further you turned the ****, and I mean flyin' wipers. LOL. I learned in my first tour, that time, to NEVER again get a military driver's license, as it meant "motor pool" time, a BAD thing. And I never got one again. Then, when I needed a vehicle, I got a private in my section to sign out a vehicle and away we'd go. But you, now, w/ the big "Deuce," is a really neat thing to drive I'm sure, and your motor pool time is fun. LOL. That's one of the coolest rides I've seen in quite awhile, and thanks f/ the great memories. I won't get into the "high performance" cigarettes that made it fun when we were cruising around in those "low performance" rides. LOL! Those were the days...the "OLD" army.

Have to ask: Is that a water or gas can on the driver's side running board? Water or gas, those were some heavy duty cans. Do you still have the tools that came w/ it, like the pick, shovel, etc.? How about the rest of the items that were originally issued w/ that vehicle? The more I look at it, the more I remember about it and the cooler it is. Great vehicle and great memories f/ me. Thanks again!!!

Oldsguy

That truck is really cool! Looks like a nice fun vehicle to own. What are your plans for it?

svnt442

That's because of the HUGE honkin generator that's hanging off of it!!!

olds 307 and 403

The jet size is marked on the jet itself. Carbs unlimited is one source. The 400 carb should be close but slightly lean. The Olds 403 carb from that year had 73 jets and 43 or 44 primary rods, can't remember. A quality timing set like a Cloyes Street Roller is a nice, accurate set. Cool Truck.

Yellowstatue

OK Back to item # 3...the front left bracket is for the alternator...it hangs upside down compared to a non AC car....I didn't realize there was a HUGE honkin generator at the end of that other bracket

Warhead

Waaaaay cool project.
BTW, how is the power transferred from the engine?
It sure does'nt look like there is anything bolted to the back of the engine...
A BLAST of a ride.
Jim

Gunfreak25

Wow! I want to thank everyone for the replies! Must have missed the email notifications.
Texas Jim. I want to thank you for your service! I have met many vets and enjoy listening to the tales they have to tell. Combat vets or not, it makes no difference to me. Everyone has their job to do and one thing must get done before another can, everyone scratches everybody's back. That is indeed a genuine WWII 1944 dated WATER can on the side. I plan to clean it up later and suck the rust out of the inside with my electrolysis setup. I do not have any other tools with it nor do I know many other G749 owners who have tools. They are very scarce and rarely show up on evilBay.

Oldsguy, I plan to fix it up for what it is. A "big green army truck". I'm fortunate enough to live in a small town, the truck will serve as a semi daily driver. Another reason I opted for this deuce is the power plant. I thought it would be better suited to stop and go city driving than the more common Multifuels with Spicer 5 speed standards. I'd burn up a clutch in no time!

I see some of you spotted the generator. Big dinosaur! It should still work and the only reason they rigged it up was for the fan belt. It should make putting the rest of the truck back to 24V fairly easy.

Warhead, it has a Th400 behind the block, can't really see it. Fairly common engine/tranny swap with this particular truck.

Progress has been real slow. Was a bit demoralized a few days ago. It's real easy to get overwhelmed with such a project and the thought of setting fire to the entire truck has crossed my mind a few times. Just gotta keep on truckin and get er' done! With that being said, if someone offered me what I paid for it (maybe less) I would consider letting it go. Hind sight is always 20/20 and I should have bought myself a CUCV or small truck. Being 19 years old with less than enough income to live by myself on I should have saved something like this for retirement. Only choice I have now is to fix it up and get it on the road because I doubt there's another SOB out there as crazy as I that would buy this old girl like I did!