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

[jeffspower]

Cool. I used to work on a '68 Mack fire truck with a gas motor. It was basically their diesel motor converted to gas.

[cayoterun]

Still the tranny overdrive search and possible options:

Allison Auto questions:
#1: Are they available without electronics?
#2: Could the torque converter be bolted directly to flywheel with a machined adapter, then use a custom machined adapter from tranny to bellhouseing?
#3: Most of all, Is overdrive available in them?

As discussed before here, we're dealing with weight, space, simplicity, ratios, and affordability.

I do have some good prospects on 5spd manual overs, but none in hand. When we get a tranny in hand and matched, then it will be time to start stripping frames and mounting.
Thanks,
Cayoterun

Side note: It's tempting to run without a hood/w 12 stacks sticking up. silly? comments welcome----"Balaur" needs to live up to her name.

[watahyahknow]

no info on the allison but i know the 4L80E is adaptable to semi automatic http://www.the-transmission-center.com/
here's the text on it : #1. Quadzilla Shift Kit - Full manual shifts - the transmission will be in the gear you select and changes to any gear you choose when you move the selector. No computer or wiring needed, rated at 900 + horse power and has full throttle 3-4 up-shifts. This is the Street Rod transmission of the future, as more and more people install motors with over 500 horse power. Cost $295.00.

[jeffspower]

1- yes
2- first part, probably. 2nd part, not needed it you get one with the correct SAE housing on it already.
3- yes, but I think all of the OD units are electronic, and are very expensive. A 2200RDS thru 2700RDS model would work nicely, they have a stand alone computer but still have a mechanical shifter. But I bet a good used one would set you back 4 grand or more. We see them in new trucks at work behind 5.9 & 6.7 Cummins engines. Once in a while behind a C7 CAT or IH DT 360 or 466. A 1000RDS would be plenty stout, but probably not found with your SAE size.

[Lated]

Originally Posted by watahyahknow

no info on the allison but i know the 4L80E is adaptable to semi automatic http://www.the-transmission-center.com/
here's the text on it : #1. Quadzilla Shift Kit - Full manual shifts - the transmission will be in the gear you select and changes to any gear you choose when you move the selector. No computer or wiring needed, rated at 900 + horse power and has full throttle 3-4 up-shifts. This is the Street Rod transmission of the future, as more and more people install motors with over 500 horse power. Cost $295.00.

I think you missed a 3 in your price

[cayoterun]

Either of the autos would be great, but bigger than my pockets. Interesting to learn of the 4l80E set-up. I sure like the stock one in my 1-ton.

I changed to the smaller flywheel, clutch that was standard on the 478 V6 trucks. I ask for 478 parts now, because some guys think your a nut when asking about the 12s.

5 spd over trannys used by GM:
New Process 540GO14
Clark 264VO
Spicer 6853C
These trannys will probably be found in GMC 5000 (early 1960s) or bigger trucks behind 478ci V6 (or V12) engines.

Tranny front specs:
Input shaft: 1 1/2", 10spline, throwout bearing nub 1", Shaft Length 8 1/2" front tranny case to end of nub.
mounting bolt holes: 8 1/2" horizontal, 4 5/8" vertical.
Top shift, but would settle for a cabover linkage shift.
SAE housing size #4

I've looked at some trannys in trucks, but some of them didn't have data plates on them, so made it hard to identify.
Thanks,
Cayoterun

[bigunde]

http://www.transmissionadapters.com/...%20&%20V12.htm

[watahyahknow]

Originally Posted by Lated

I think you missed a 3 in your price

thats for the shiftkit to convert to manual

[cayoterun]

I got all pumped up about this, 'til I saw the price, then I fizzled & spluttered like you'd turned the end of a ballon loose.
Thanks for posting it, bigunde. I can always drool, but fight credit card bouts of insanity all us old car/truck nuts suffer now and then.
Great setup. Glad it's available, at least it adds another option.
Cayoterun

[watahyahknow]

think you can make youre own adapter from a piece of inch thick aluminium just make a gasket from the engine and the trannieface lay them over eachother and draw a cthirt one covering all the boltholes needed cut this out with a eeeeh electric saw thingie or bandsaw and then put the holes and treath in it with a drillpress , you still need to have some sort of spacer turned on a lathe to get the torqueconverter in the right place again

[cayoterun]

Exhaust pipe paint? ------ Does any of this hi-temp spray can paint work at all on exhaust pipes. I'm not looking for any thing fancy, maybe something to keep them from rusting. I'm starting to build some stacks for the motor and as crazy as it seems, from square tubing, and point them up. One from each cylinder. I need to get the noise up higher so people won't have to wear ear protection and still hear it. They have made square tubing headers for them for years, but they were all horizontal so rain wouldn't get in them if they died during a rain shower. This may just be a temporary deal for while it's still in the stand. Just wondering about some of the stuff on paint shelves, but never used any.
Thanks,
Cayoterun

[slug]

have you ever thought of mounting the engine and tranny in the bed faceing backwards and useing a v drive from a boat?? i seen a episode of monster garage where jessie used a v-drive to make a ambulance do a wheelie. that would get the weight of the motor over the rear axle, or even give you room to move the engine/tranny where you wanted to get better weight distribution.

[Lated]

How about using a Pontiac Tempest trans-axle

[cayoterun]

Slug: There's been several similar configurations suggested in prior posts and all are worth consideration. I think my favorite is the one with the motor in front on the old time "Jalopy".

Lated: The trans-axle idea is good, but it would need to come from something such as a pusher bus, as a car set-up wouldn't be beefy enough to stand the torque this motor has.
I spent almost all day today in a large salvage yard looking for a tranny, and came up empty handed.

Finished roughing together one set of three stacks, (one head), Bolted it on, and ran it for awhile. Kinda' good to be able to hear each cylinder individually, but not convinced this is permanent tho. It may bring too much heat up around the top of the motor and add to the cooling problems, I'm sure we're going to encounter.
May opt for 4 real quiet mufflers. That thing is LOUD in a metal shop.
Thanks for all ideas and support.
Cayoterun

[54 jimmy]

what about putting that moster in a older c-50 truck. it would probably fit and they are big and beefy. kinda like this 1968 c-50 truck

[89 crew]

For a transaxle have you looked at the 78 Cadillac Eldorado? It might be able to hold it.

[cayoterun]

54 Jimmy: Something like that would be the practical thing to do. When I started, I had a non-running motor and the ideas just kept coming and by trying to combine them to have a functional and unique vehicle to show the motor has become my goal.

There's a V-12 single axle truck posted on 6066 GMC website at Tulia, Tx. that sure needs to be restored as is, if anyone would be interested. It's too nice to be cannabilized or salvaged.

89 Crew: I had never considered anything from a car assuming none of them were stout enough. I could sure be wrong.

Due to spine/vision giving more trouble, progress sure seems slow.
Thanks,
Cayoterun

An invitation: Anyone passing through this area and would like to hear or see it run, your welcome at our place anytime. Bring ear plugs.

[cayoterun]

Test Fit? Left side. Sounds Good, Looks ??
Truck is in Tulia, Tx, mention in previous post

[Storm Chaser]

cayoterun, are you on vacation, or what? Any progress?

[cayoterun]

Still dealing with the tranny question. I WANT? a 5spd over, but seems like they are as hard to find as one of the old motors. I'm trying to stay bolt on without adapters and machineing so if someone wants to do another, at least we will have some bolt up components that will work. You guys led me to a source for faster rear end gears, so know they are available.
It looks like that is what I need to use considering simplicity, weight, cost, and space. BUT, where is one??? There's one out there in the weeds somewhere, I hope.

I've got the 12 stacks built, and painting them now with hi-temp paint. They are just a "show and tell" thing and not practical at all, but sure have a wild sound. Will try to get my son to post a video in a few days.

Appreciate all you guys help and interest in this. I'm amazed at the all the e-mails and phone calls I receive, as here locally they were so abundant, we thought everyone knew of the old brutes.
I can't stress the fact enough that the old motors are NOT suitable for hard use, unless money for parts is unlimited, if you can find them. They are great for easy use and a conversation piece.
I'd like to see more of them restored and shown. They sure create lots of debate and are certainly a neat part of GM history.
Excuse the long winded rant.
Cayoterun

[b454rat]

Not sure if it's what your looking for, but I have a NV4500 that I can't seem to sell. But without special adaptors, not sure how it would go together.....just thought I'd throw that out....that thing is sweet BTW!!!

[cayoterun]

Stuck the stacks on today. It reminds me of an old motor out in the woods with trees growing up thru it. Sure has a wild LOUD sound tho. Will try to get a video in a few days.
Cayoterun

It looks like red overspray down low near the head on left side pic. Must be reflection from camera flash. ???

[cayoterun]

b454rat: Wish your tranny would work, but won't come close to fitting. I've got to get up in the 2ton-road tractor size and back in the 60-70s era to score one. I know they are surely out there, as I've drove them back then.
Thanks for the offer
Cayoterun

[89 crew]

Check this link if you haven't already. There is mention of some of the transmissions that were originally mated to it. This is a rebuild manual for the v6's and v8.
http://oeltd.net/Doc/GMC_Manuals/X-6A-01/

[89 crew]

Oh, one more link I found. This is a transmission shop selling adapter kits. For the 702
http://www.transmissionadapters.com/...%20&%20V12.htm