702 GMC V-12 powered '62 GMC 1-ton

[special-K]

Use a strait axle or better yet(I love spending other`s money)use a 3500HD frame.Much easier and heavier being a strait rail frame.I`m sure you could mount your crewcab on fairly easily.Check my avatar for a stretched nose big Chevy.It`s a puller that runs the V12 Detroit.

[cayoterun]

That makes my gasser look like a pup!
When you drop the clutch on that, one of three things is going to happen: Wheels spin, something breaks, or things are gonna' mooove. I'm bettin' on the latter!
Heavier frame and axle would solve alot of things, but I'm holding on to keeping the innocent old, ratty 1ton look as long as I can, but I'm sure lots of changes will be made before this thing moves, (if ever).
Engine in bed? That's a new thought.
If this thing ever flys, I'll park it by Johnny Cash's cadillac.
Thanks,
Cayoterun

[ChevLoRay]

I don't think you'd like the drive if the engine was up-front. It's a lot of weight and moving the cab back might make for an interesting hood/fender appearance, but I still think that a mid-ship mounting would be best. If you don't intend to do anything but show and brag, then what difference would it make? A one-ton chassis shouldn't be an issue. If you just want to get it to the roller status, then all you need is enough transmission to make it move.

Besides, you could get a Gear Vendors Over/Under drive unit and step it up. Put an SM-420 or SM-465 behind it....but the gearshifter is gonna be "odd". Automatic, even a GM dual-coupling hydramatic, would be the best ticket, in my opinion. But, it's your money....spend it!! You can't take it with you and you don't want the kids to fight over it, do you?

[cayoterun]

I with you on mid-ship. I would like a drivable truck as end product. I never was a trailer queen fan, nothing wrong with show quality, but personally, I like to drive and use the stuff I put together and I live in lots of dirt and mud. Fuel consumption is the limiting factor on use. Tranny choice is optional. Just something beefy enough to stay in there under sensible use, AND the cheapest.
Thanks, All
Cayoterun

We're in the SKI group, too. Lovin' it, Price of fuel, won't take long. LOL

[cayoterun]

Motor Length: I measured from tip of water pump shaft to rear of block. Almost even 5 (five) feet. Outside-outside manifold width is 24".
The 454 length is about 32" +-.

Front Axle weight: After comparing engine weights of a big V-8 to the V-12, it will add about 600# to front axle. I checked the data plate on my '97 Chev 1ton, and it lists 4100# GAW for front. I'm hoping the weight factor is doable since the truck won't ever be hauling more than a 1000# or so in the bed if we decide not to move the motor back.
Am I overlooking anything?
Cayoterun

[jeffspower]

If you don't mind that the front end will sit lower & feel a little mushy, I don't see a problem. Guys run snow plows on little 1/2 tons all the time and get by. While most plow setups ain't quite that heavy, they are hanging WAY out front. You can bag the front springs too.

[Scott68-93-97]

Im gonna say mid engine big tunnel maybe a homemade body lift because you can make it better than any you can buy by raising the body mounts instead of plastic spacers, youll have to make some interesting linkage for the shifter but hay I think minimal modification is out the window at this point

[cayoterun]

Happy and unexpected reunion!!!
First, I'd like to thank the couple pictured, Ted and Darla Summers, who made this reunion possible for this old engine and I after 43+ years.
The engine was put in service in 1964 on a new irrigation well pulling a 10" pump, pumping 2,000 gallons a minute.
I came home from overseas in Jan. 1965, went to work for the owner at that time. Cared for it for a year and changed jobs. The first owner (MMMallard, now deceased), used it 'til 1972, Sold it to this couple, and they ran it 'til sometime in the '80's. The motor broke a head, so he replaced it and put in the barn pictured. He learned I wanted to put a V-12 in a truck and told me what he had and if I wanted it. I jumped at the chance, then to add to my amazement, He said she's yours, FREE, bring her back to life.
Today is the first time she has seen daylight since the 198?
So this is the engine I intend to rebuild to running condition ( new internal parts are all no longer available) and put in the 1ton in all her former finery, which is pretty plain.
What a coincedence!
Cayoterun

[67_C-30]

That is going to be an awesome project! I have a 351M V6 that I am dying to put in something myself. I have never seen one of the the V12's in person, but I can imagine how big it is. The V6's are huge and that is essentially two of them inline! FYI, if you didn't know all of the internals of the V12 like the pistons, rings, rods are the same as the 351. They have the same bore and stroke. 351 + 351 = 702

[68GMCCustom]

considering the size and weight of the V12....have you ever considered rebuilding the engine and making a custom trailer for it? And it could power something, for show purposes....? Then pulling it behind your '91, or even something older?

Just a thought.

[cayoterun]

There a several of those type demos through-out the plains states, and are really nice. They are alot more visible than this idea. I haven't seen one similar to what we're trying to do.
Would be fun to tow a trailer to the mountains and let those drivers of new trucks try to figure out how that old truck was hung on their rear bumper on long grades.
Based on everyone's imput and ideas, there's no telling where this project will lead us.
A standard cab flat-bed 1ton is already in the mix for consideration. Shorter wheel-base.
Thanks for all ideas and debate.
Cayoterun

[Storm Chaser]

Hmmm... 4 exhaust maniflods....

QUAD TURBOS!!!

[ChevLoRay]

Speaking of trailer-mounted....

Before I retired, we'd have a company come into our plant, periodically, and clean some big tanks for us. They had a flatbed-mounted V-16 engine that drove a pump. The engine was HUGE!! It would make four of your V-12's to equal the overall length of that beast.

I used to belong to a car club that had joint shows with the Rusty Wheels Engine Club, here in Arkansas. One of their members, also one of ours, had a 1960 Chevy Conventional cab tractor (single-axle) that pulled a low-boy trailer. Mounted on that trailer was a 1920 Fairbanks 2-cycle diesel that had been used to drive an irrigation pump near the rice fields of Stuttgart, AR. He nicknamed it Miss Smoke Rings. It took a 3-horse hit/miss Fairbanks engine driving an old air compressor that was used to start the diesel, after he had built a fire on the head of the cylinder. Once he had enough pressure and the head was hot enough, he'd grab the flywheel (it was about 6-feet in diameter) and start trying to start the engine. Once he had it running, he'd idle it down and add fuel to it, You could count the RPM's by the number of smoke rings that it would shoot out of the exhaust pipe...a pipe that was 12-inches in diameter. Best I remember, it would idle at something like 30RPM's.

[NONHOG]

That's cool ! saw one years ago @ the Portland swap meet .Never forgot it
I think there is alot of good idea's however I can't shake the idea of that
engine under cab as in one of those early COE model's mid 50's or earlier
with your 91 frame modified to order ? GOOD LUCK whatever you choose
can't wait to see where it end's up !

[JameslovesJammie]

As far as transmissions go, a split gear SM420 from a 60-66 GMC 2 1/2 ton truck would work, but I have NO IDEA how you would shift it if mid mounted.

The SM420 has the same bolt pattern as the v-12 since it was mounted behind thousands of 305 and 351 v-6's.

[Mickey_D]

What I think would be cool as all get out would be to mount it in the bed (I mean in, not on. Partially submerged would be a good explanation) and run it mounted backwards (flywheel forward) then have the driveshaft run forward to a transfer case flipped backwards in 4lo (to double the engine's output speed), then have the prop shaft run back to a flipped axle.

You've definitely got enough torque there to to run in 2:1 overdrive, and that would get your powerband up in the 60mph range (I would think).

Then just bolt in a non-operational 260 V-8 out of a 70's Cutlass or something ridiculous like that as ballast and for the head scratching effect. Fashion up a hinged hard cover for the bed to hide everything.

As for shifting, take a look at how the old Diesel pusher school busses work it all out. They've got the driver at the front of a 40 foot long bus and the tranny at the very back. If they could do it there, you should be able to copy it for the relatively short distance for yours.

[Pyrotechnic]

Maybe mount the front half of the engine in the cab, and the rest in the bed ? Then the problem is no room for a transmission between the rear of the engine and the rear axle, but if you stretched bed and frame a foot or two though, you'd have plenty of room for the transmission. The only give away would be the looooonnnng bed.

[cayoterun]

Now that I've found THE engine. I'll focus on getting it and the drive line up and running in the stand. Pulled the rear heads and pan today. .30 over pistons, and standard shaft. Cylinders fair, bearings in good shape. New hard parts are not available. Ordered a complete overhaul gasket set. Over $350.00, Ouch. Looks like grease and dirt removal is the biggest job. It'll run ok after a good cleaning in and out. Crazy as it seems, I'm trying bring it back as near like it was when shut down 2? yrs ago. There's no way to determine how many hrs. or equivalent miles it has on it. No one remembers how many rebuilds it had.
Cayoterun

[Mickey_D]

Or using Pyrotechnic's idea and running a chain drive down to the axle. Much like Saab did from the engine to the tranny in the 900's.

[ChevLoRay]

Remember when Olds brought out the Toronado in '66? Remember that they used a chain, as it was called, to get the power from the 425 engine to the TH transmission? You could use a version of that to do the power transfer, if you didn't mount it conventionally and use an SM-420 or SM-465 gearbox.

It's gonna get gnarly before it's all done. Then, it's gonna BE gnarly!!

[cayoterun]

Considering the age and use of the motor:
What would make it more interesting. Clean it as well as possible, then reassemble as is with no paint, or paint it?
Let it show it's age, or look cleaner?
Cayoterun

[cayoterun]

Paint: Had to use a 4" grinder to get crud off block and pan. It will get new paint.

Inside: Was full of carbon and gunk. Found dead mice in one head. How do they get there??? Some rings were stuck. Sure glad we tore it down and cleaning everything. Crud on scraper was on top of one piston.

Based on length, Can we call it a long block?

Progress: One bolt at a time.
Cayoterun

[Storm Chaser]

Dead mice?

That's why it doesn't run! You have to replace those mice with good ones and lube the treadmill!

[cayoterun]

Worked them to death, huh? Next ones we'll let 'em run slower and grease the wheel. Good One!!
Thanks for a good laugh,
Cayoterun

[72armyswbtruck]

I can't wait to hear it fire up someday