Rare or Odd? 66 C30 Dually Q's

[Americanrider]

I happened into a '66 C30 that began life as a factory Motor Home, from what I can see of the option sheet (still stuck into the seat back springs but way to brittle to remove) it has Power-ram steering, Power brakes, 4sp SM420 w/ trans brake, front sway-bar, 4 core Rad and rear dually axle w/ overloads.

The camper part was removed years back and set up with a PTO driven Flat Bed dump. The truck was a wood hauler until the PO removed the 327, it sat for 5 years and then he gave it to me. She's rusty/crusty and shows 72K original miles which I think is correct. I'm planning to part out the ol' girl this next summer and it's raining to hard for photos.
No, nothing is for sale at this time please don't ask.

The odd things I noticed yesterday was when I shined a flash light behind the dash I found two red round warning lights, one to each side along the lower level of the dash gage cluster.

The one on the left says:

OVER
SPEED

the right side says:

TANDM
LOCK

This is only the second truck of this vintage I have owned, the other being a '62 1/2ton long step way back in the 80's. Can anyone tell me if these trucks came with a such a thing as a "SPEEDWARNING dash" or something like the 67-72's had? What about the Tandem lock? The rear axle looks like a plain ol Eaton HO72 to me. I cant find any extra wires/cables running to it that would active a locker or make a dash light come on. Can anyone explain these features?

[b454rat]

The speed warning and tandon lock are normally used on a C50s and bigger. I buddy of mine owns a junkyard and had a 61 Viking IIRC, I snagged the dash because it has a tach. I noticed that it had the lights in it to. It used to be a car hauler for new GM vehicles. Don't know how rare they are tho.

[C10 - C90 Bill]

Tandem Lock to me would mean locking both axels to drive on a twin screw, tandem axel truck. It could be that the dash you have could have also been used in tandem axel trucks or like mentioned above, someone may have switch it from a larger truck.

I never heard of a Speed Warning in these old trucks, but I do know they were options in cars. I actually had one in a '67 Impala. But it wouldn't surprise me in the least that it could have been an option in trucks back then.

[Americanrider]

Do you have any idea of how the speed warning was hooked up? If the dash (or whole cab) did come from a C-50 & up twin axle type of truck do you think it was an engine governor of some sort? Since the tranny has the rear E-brake drum and the locking handle on the right side of the hump you could be correct. Perhaps the seat was just swaped into this other cab. Does anyone on this board own a C-30 motorhome that I can compare it to? I'll go check the vin plate against the title and look for clues to see if it might have been a cab swap. Thanks for the input!

[C10 - C90 Bill]

Altho possible, most likely the cab was not changed as the way I understand it 2-Ton and larger trucks have different non-interchange-able mounts. What you have described sounds like an typical 1-Ton set-up.

On the warning light I would say that it is just a speed minder option.

You could also decode your VIN tag for more info.

[6066gmcguy]

The truck sounds right for a C30, other then the Instrument Panel, which would have come form a BIGGER truck with Tandem rear axles. I'll bet it has mostly all gauges instead of warning lights.

The overspeed was a warning of too many RPMs on the engine, mostly used to let you know you were going too fast down hill, and the truck was pushing the engine instead of the other way around. Most big trucks had a gov. on the engine, but it would not work when going down hill and that is when you would overspeed the engine.

MY truck is a 1965 GMC 2500, which is about the same thing as a Chevy C30, except my truck has a truck engine, the GMC V6. I pulled a Instrument Panel from a big truck to get a tach, some of the lights I got in the deal that would through off any one getting the truck after me are Low Air, Diff Lock, if I was to leave them in, But I'm changing them to something I can use later.


My Big Truck Instrument Panel Enjoy.

[wahl4m]

i have stripped several pick-ups thru the years and have noticed most dashes have "over speed & tandem item in non lite bulb sockets ! it was gms way of saving money ! thanks mike "carryallman" wahl