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

[tommie]

looks great!!!

That is going to be a wild headturner when you get it on the road..

[Storm Chaser]

Wow, that's a pretty good looking cab! You just don't see 'em like that around my parts. You're doing great work there- keep it up and keep it coming!

[Palf70Step]

That is wild looking!

[cayoterun]

Hit an interesting detour. This cab is from a different year model 3/4 ton. Has more rust than the one from the '62 1/2 ton which I plan to use. Was just going to use this one for a pattern for cab mounts, etc. to reduce the chance of dings, and bangs on the "good" cab during fit. Rechecked both, and found cab mount location and some other stuff was different than the good cab.
Soo, it's off with this one, and use the good one for fit. '62 cab has very little rust, but some dinged doors typical with this year model trucks, but alot easier to repair than structural rust damage.
The front clip will end up being a hollow shell/w a fake 26"+- extention panel to accomodate the motor and big radiator.
Hoping to get Turbojunker's look, post #150,/w no hood, maybe some tool boxes under the bed, lower rear end some, and running boards for old people.
There are bits and pieces of all you folks ideas incorporated in this, so
Thanks,
Cayoterun

Add: If someone wanted to chop a pic with the added wants mentioned, I'd appreciated it. Need one to print & post in shop for inspiration.

[cayoterun]

First fit '62 cab and clip
Looks like the clip will be stretched about 28" and overall hood length about 6'4". Probably stacks will go and 4 exhaust pipes under cab later on. I think they make it look too cluttered. What do ya'll think?
Cayoterun

[watahyahknow]

it doesn't look to bad now that i see it in real life with the streched noze
maybe you schould make the exaust like they have on old fighterplanes like the mustang sticking out the sides that makes it eazier to stick a bonnet on there too .

imagining hitting the trottle driving next to some import with the windows rolled down

[Palf70Step]

It's coming together pretty nice. I like the stacks, but wonder also about it being nicer looking routing underneath.

[cayoterun]

We need to reduce the exhaust noise also with mufflers of some kind. The noise level is so loud above an idle, you couldn't stand to drive it. It would be ok for a parade, nothing else.
Passing a small car might blow all the windows out. It sure makes the metal shop rattle.
Cayoterun

[Storm Chaser]

Does the exhaust ports match up to any popular V6 out there? If so, you could maybe get 2 pairs of "shorty" style headers.

That thing is lookin' pretty wild!

[cayoterun]

Good Idea. I'll look for headers for the old V6s to see if anything is available that might work.
I had it running today, and those stacks has gotta' go. Not only loud, but with the fenders, it's almost impossible to work on the motor. I'm afraid some kind of custom headers will need to be made. The pipes will need to come over the top of the frame and back on the outside.
Our son pulled some 5" chrome mufflers and stacks off his Pete, so we were thinking of maybe trying to build a reducer for the headers to those stacks and run them horizontal on the outside the frame under the cab, then tip them out in front of the rear tires. They have heat shields around them, so burnt legs shouldn't be a problem. Improvise as we go, then do it again, right?
Cayoterun

[watahyahknow]

if push come to shove you could use the original cast headers and make a y pipe to the pete exaust , if you find the shorty header for the V6 it just might be they fit in place of the originals on the adapterpipe

or youcan make one big log type exaust 12 in one out can make it in stainless and it will look good , its not a performance item so you should be ok and it dampens the sound too
i found this one rod runnin logs thats a bit fuzzy don't mind the flames its just for the idea

YouTube - Voodoo Diablo blowin flames

[cayoterun]

Watahyaknow, When you call it a "log" type, are you refering to something like this? If so, I imagine that's what will be needed for space reasons.

On something like this, do you guys ever get what we call "Think blind"? Thought process seems to lock up on one idea, then someone suggests something "outside the box" and bingo, they have the obvious solution.
Thanks for the help
Cayoterun

[89 crew]

If you want it to be quieter, go for 4 standard mufflers.

[joe231]

very cool!!!
nice work

[watahyahknow]

its kindah like that only it connects to the head itself 6 pipes going in the big log/ tank like thingy and from there the propper sized pipe to the pete stacks you might be able to make some sort of dampening material on the inside of the log but not mush it most likly will only stop the machinegun sound when you lift the trottle

[cayoterun]

Here's to ya, Mickey D. Thanks for the name. Balaur has 4 dragons/w three heads, each head firing one cylinder.

Exhaust manifolds/headers? There's plenty of room for about anything, except the left front head. We only have about 4" of clearance between head and steering sector. I'm sure it will take a homemade manifold of some kind.

[bb1979]

Cool project, I read that you sourced another piston from a junker motor but did any of the other leads eg Egge result in new pistons being able to be sourced.

I only ask because a hot rodder here in Australia is installing one of these beasts into a 32 Ford 3 window and his pistons are toast

[thirdstreettito]

Hmm, what about tranny?

[cayoterun]

For my use on this, I'd like to find a 5spd over manual from behind a 401 or 478 V-6 GMC truck and use as high a rear end ratio as possible. GMC used New Process, Clark, and Spicer, but so far, hard, hard to find. I do have a 5spd direct and 3spd aux that can be used, but wouldn't be as simple as an overdrive. There are other options such as a custom adapter for Automatic use, but very pricey. Final choice hasn't been made on this. Lot's of fitting and fabrication to do on the other stuff.
Thanks,
Cayoterun

[cayoterun]

Sorry, bb1979. I overlooked your question for piston sources. New pistons and internal parts are almost non-existant. There are places that will custom-build them. All parts new, or used are pretty pricey. When I was looking for pistons, a salvage yard told me he sold used pistons for $80. each, but didn't have any. I was never able to find any source with anything in stock. Good source for info and leads is www.gmcguy.org.

Exhaust manifold: This is what I finally came up with to get past the steering box. I'll probably need to wrap it with insulation as it still runs close to valve cover and steering box. I cut the stacks, connected them, then down & out. Steering box sits in front of pipe. Crude and rough, but hope it works. For now, will use stock manifolds on the other three.

Tranny: Another guy is working on an adapter for an T400 or 4l80E auto. It looks good so far, but not finished. An auto would sure simplify things.

[Hart_Rod]

Just spent over an hour reading your thread.........this is one of the coolest builds I've seen! Glad to see another Okie likes big trucks, .

[cayoterun]

Body mount position?

The belt line of the body--front clip, cab, and bed,---needs to run parallel, (level), with the frame? Is that right?

It's time to start mounting body mounts to frame, and wanted to be sure.
Thanks,
Cayoterun

[MonteSS454]

Why don't you just run stack behind the cab like a big rig?
Just collect all 4 header pipes into 2, run a muffler on each side under the cab then stacks behind the cab?

[Damien]

Does the V6 share exhaust ports with a V8 that headers could be gotten for such as a big block chevy? If so, one tube could be cut out.

[cayoterun]

MonteSS454: I like the idea of stacks behind cab, but having a 60gal propane tank mounted on bed in that area, holding indirect heat away from it would be wise. By dumping exhaust underneath would make the safety inspectors alot happier, whether the stacks would pose a safety threat or not.

Damien: I don't know if a V8 header would match. There are headers made for Jimmy V-6, but since this is mounted in a different frame (F--d), headers would have to be custom, so we have ended up with this homemade set-up 'til we see how everything else comes together.

Progress: Radiator is mounted independent of front clip on its own frame crossmember. It's a 5 row tube industrial radiator.
Front clip can be removed by pulling about 8 bolts, and truck will still run and could be driven. Probably no hood to start with. Cab can be pulled by about the same # of bolts, and a few controls and wires. A bunch of improvements could/will be made later.
Tranny question still undecided, but hoping to use a T400 auto tranny.
I ask OHP about front fenders. They think we could run w/o fenders and front clip as long as we have the required lights in front. They couldn't find any statutes that specified certain requirments for FRONT fenders in Okla. REAR fenders/mudflaps, yes. Note: Important body working tool in floor. (trusty sawzall).

Thanks for all the suggestions. There are bits & pieces of any/all used in this, so let's keep thinking outside-the-box.
Cayoterun