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

[HotRodYJ]

Seriousley cool build! I've not taken the time to read everything but the one thing I think would deserve the extra effort is custom headers. You can buy header kits from Summit and Jegs to build your own. Probably have to cut your own custom flanges to bolt to the block, but other than that it's just bits of bent tubing you match up and weld to whatever fits your application. I'd hate to see such an awesome build go by without a good looking header to match the rest of the project. JMO.

[watahyahknow]

i dont know if hey make headers for the V6 version of that engine but if they do you could use two and connect two into one pipe or use 4 mufflers

[HotRodYJ]

How about more of a traditional HotRod header with rod tube similar to this. Still be pretty easy to make yourself, but a much cleaner look.

[cayoterun]

Cab will be removed next. Th400 tranny & adapters should be ready to fit soon.
Pic#1 shows the close clearance we have between manifold and steering sector. Less than 4" from head to sector. Can't go down or the header pipe would have more crooks than an Arkansas backroad. (I'm a natural born Arkie). Hotrodyj, I agree that some custom headers would look much better, and are on the dream list. There are headers available for V-6s, but no room.
whatahyahknow, I thinking now to use flexpipe from what we have now to two glass pac mufflers mounted under the cab on each side, outside of the frame, then pipe back tipped out in front of the rear tires.
Pic#2 shows one good thing. Brake booster and master cylinder will be an easy graft from the F---, so booster, master, proportioning valve and all will match same donor truck.
I was glad the header pic was posted. It also let me see someone else used small u-joints and shaft for steering. I can get truck pto shaft locally, and it's heavy built. I think I'll only need two u-joints, and will use a square shaft & slip joint to absorb frame flex.
Pic#4 is where I'm at with extended clip. It's only a fake hull. Sure would be nice to have a flip clip like road trucks, but another dream list item for now.
What do ya'll think?
It's been 1 yr on 9-11 since we drug "Balaur" out of the barn and started this. I won't use the word "celebrate" as I can't think of anything to celebrate on that day.
Thanks
Cayoterun

[Storm Chaser]

I won't use the word "celebrate" as I can't think of anything to celebrate on that day.

Sure, you can use the word "celebrate" if you want. In our house, 9-11 is treated like a holiday. We watch the movie "World Trade Center" every year and whatever special might be on tv. Then we have dinner and remember the police and firefighters who gave their lives and honor those that still do every day. We honor those people who went to work just as they always did, but lost their lives. They were and still are the spirit that makes America stand out in the world. They died doing what makes this America- freely going about ther lives- going to work to make our economy and country run while making a better life for themselves. Just like the troops (who we also honor on this day), they died Americans- Americans doing what makes this America. You don't have to celebrate the attack or the fact that people died, but it's perfectly OK to celebrate their lives, the loved ones they left behind, and the fact that they didn't back down even in the face of death.

Yes, 9-11 was a tragic event, deserving of remembrance, honor, prayers, and even a celebration of sorts- celebration of American spirit.

You can do as I did, and dedicate your build to the victims of 9-11 and to the troops defending the very freedom the terrorists don't want us to have.

[cayoterun]

Thanks for that point of view, Stormchaser. Never thought of it that way.
I may do the dedication. It would be a small way to show my respect for the lost. I didn't want to say anything that might imply I was trying to minimize the importance of respect for 9-11.
Cayoterun

[kevinr1970]

I read the first few pages when you started this thread and just read the last few. I will go back and read the rest when I have some time.

With that in mind, for your hood here is a suggestion (sorry if you have this worked out already).
Maybe you could do a hood to match your front clip ('62?), but open forward like a tilt hood/front clip. Then take another hood and cut it down for the amount to fill the gap (28"?). That section would open normal. Have the full size, front part of the hood close over the top on the rear section to keep it closed.

For your clearance issue on the radiator, you could do like a cowl induction hood down the center but on the front end do something like the late 60's/early 70's Olds W30 hoods that ran all the way to the front of the hood? I know the W30 hoods had "dual" raised portions but what I mean is to extend the cowl part and have the front end of that like one of the W30 hood "scoops".

Looks awesome so far. That extended nose just looks cool as all get out!

[cayoterun]

Kevin1970, I think you rattled me outside-the-box on the hood. The front clip is complete, except inner fenders trimmed. The rear 30" is the back part of another clip. I left both clip frames so 2 sets of hood hinges could be used if we used a two piece hood, both hinged from the back.
Using your suggestion on the tilt front/w front hinges, and rear hinges on back part that would open the engine compartment to make the old engine more visible when open. I could have a local metal shop build a scoop to accomodate the radiator, and also use a baffle in the scoop to direct more air into the radiator front. I need all the air thru that radiator I can get. We'll see what this leads us too later in the build. Sounds great now.
Thanks for turning the better "idea" light on.
Cayoterun

[sutton82]

I say make it look like this: http://www.hotrod.com/featuredvehicl...evy/index.html

Just kidding. This is an awesome project.

[special-K]

I`m enjoying your build.I can`t wait to see how the exhaust gets done.
Here`s something for fun:

[cayoterun]

Sutton82: Thanks for the Blastolene link. Most details I'd seen.

Special-K: There is/was? a one owner truck like that not far from here in Tx. Had to really slap hands to keep from buying. It needed to be restored, but a great foundation.
It was parked beside a big shop a few years back. Tornado came thru, destroyed the shop, but two broken windows were the only damage to the truck.

My project is kinda' on hold. Waiting on one more adapter to be machined. Trying to use a TH400 tranny. Once we get a tranny mated, then maybe we can start making faster progress. When it's mated up, then try to put faster gears in rearend so we can to try to reach inter-state speeds or above. The exhausts and the rest will all be pretty crude in the beginning. Just getting it to move under it's own power will be a major milestone for me.
I know this truck will never be as nice those in pics. Thanks for sending them.
Cayoterun

[Damien]

I don't know if anyone has run across this site. It looks usefull.
http://www.transmissionadapters.com/...%20&%20V12.htm
This one too.
http://http://6066gmcguy.org/TwinSix.htm

[cayoterun]

Thanks, Damien, A friend took a little different approach on our adapters. We had considered using those. Pics later.

I'm thinking that when we get the T400 mated to the motor, next week I hope, I'll try using a Spicer 3spd auxillary turned backwards. (Low would become high) Whether that will work is a debate within itself, but I'll never know 'til I try it.

Question? Would a shift kit enable me to hold the T400 in ANY GEAR, regardless of engine rpm? Preferably 3rd gear.

Reason: I need to hold the output shaft of the tranny at constant speed relative to engine rpm to shift the aux while moving since I won't have a clutch.
Old timers would say, "feelin' it in gear".

Hope this is clearer than mud.
Thanks,
Cayoterun

[Hart_Rod]

You can put a manual valve body in the tranny that will allow put it in a gear and it will remain there until you change it to another one. Good luck.

[cayoterun]

What are they called, where do you buy them, and does the tranny have to be removed to install them?
Thanks,
Cayoterun

[Hart_Rod]

Originally Posted by cayoterun

What are they called, where do you buy them, and does the tranny have to be removed to install them?
Thanks,
Cayoterun

Here ya go....

http://tciauto.com/Products/Instruct...21100_inst.htm

http://books.google.com/books?id=KKP...um=7&ct=result

http://www.hughesperformance.com/pdfs/HP2211.pdf

[locomotive breath]

Be careful using a full manual valve body, they are primarily for racing and shift very hard. You should be able to float the aux. trans. in and out just using the acc. pedal. I would probably try it first with the stock valve body and only go to the manual valve body if needed. There are two main ways to go about installing a manual valve body both of which require droping the pan and valve body assy. The kit types are cheaper and normally retain the stock forward shifter pattern (PRN321), while the complete valve bodies are often use reverse pattern shifters (PRN123)

[jeffspower]

Depending on what your TH400 is out of, most of them have pretty low shift points and go into third pretty early. "playing around" with the governor & modulator is easy to do to make it shift early & "hang on" to high gear under throttle. My '72 has a TH400 and I can shift the transfer case from high to low decent going down the road- and of course it isn't synchronized as I believe your aux. is.

[cayoterun]

Jeff: It's out of a '84 Chevy C20 Van.

Cayoterun

[68K20 x Drill]

Get the governor from a diesel Th400, and it will shift very early.

[cayoterun]

We now have a '84 Chev TH400 tranny in and running. Big hurdle overcome with the knowledge and help of two people.

I'd like to thank Jim @ Phoenix Casting Co. of Nebraska for designing and machining the #2 flywheel housing adapter ring to Chevy trannys. Great job, Jim.

The other goes to a member of this board, Locomotive Breath. He designed and built the drive plate adapter. It bolts to the optional irrigation V-12 flywheel, then a standard 350 Chev flywheel bolts to it. Very straight forward and simple design in both. Great work by both of you.

After all was installed, I run the engine up to 2500rmp at all speeds and gears in between trying to find any vibrations. It's smoother than cream and quiet as can be.
Maybe now progress will be a little faster
Cayoterun

[jeffspower]

Cool. Looks pretty simple, with a lot of thought & measuring needed to get it right. Now you can bolt up anything from an 18 speed to a powerglide!

[Conundrum]

This is an interesting build, looking forward to seeing more.

[Restrorob]

Hey cayoterun,

I read every one of the 322 reply's last week and am intrigued by this awesome build. Do ya have any updates for us ?

BTW, I once owned a 62 GMC with one of these V6's, Never knew they were the platform for this killer V12.....

[cayoterun]

Since we decided what tranny we'd use and installed, it's been kinda' dull. We have the cab back on, now trying to get all controls and linkage on it.

I was able to graft the F350 power steering pump, brake master and booster to this truck. All that is standard '72 F350 now. No one will know when we get it all covered up with GM stuff.

I'm using a '63 F### Galaxy auto steering column. If someone has a wiring diagram for the auto tranny switch on the steering column handy for sale or use, I'd sure be interested in buying one. I want to be sure that thing won't crank in any position but park.

Josh/Liz, This thread seems to be using alot of web space, so if it is too much, I'll be glad to pay extra dues or donation.

When we get the linkages hooked up, I'll post some pics before setting the front clip on.

Thanks for all the interest, support, and help from all. Even several local farmers are real supportive and glad we're bringing the 'ol girl back to life.

Cayoterun