The Stovebolt Site Forums The Parking Lot Big Bolts Need info on Mid 50's 450.

I think I'm in the right forum... I've found this truck in a swamp at work. It's been there for years. Don't know really much about these. From what I've been able to figure out so far, it's a 1955 GMC 450 grain/dump truck. I've got some pictures but seeing as the ground is still really really wet I need to wait for it to dry out a bit to check for identification tags and really get a close look at everything. It's got a big blade in the back that looks like it would fit on a big 6 wheel Cat tractor. Anyways...onto the pics!

http://i641.photobucket.com/albums/uu137/apsixsix/0317000816a.jpg
http://i641.photobucket.com/albums/uu137/apsixsix/downsized_0317000814.jpg
http://i641.photobucket.com/albums/uu137/apsixsix/downsized_0317000814a.jpg
http://i641.photobucket.com/albums/uu137/apsixsix/downsized_0317000818c.jpg
http://i641.photobucket.com/albums/uu137/apsixsix/downsized_0317000820.jpg
http://i641.photobucket.com/albums/uu137/apsixsix/downsized_0317000814b.jpg

Thanks for any info!

Never thought I would see a time you need to fire up a chainsaw before driving your truck!

These are my best "guesses", Fatman. Probably right but there are always exceptions.

I agree, one of the 400 series, 450.. 470, who knows. Short frame, likely a 3 ton.

Engine would be a 270 or a 302 cubic inch. I would bet a 302.

Clutch plate is 9.5 inch (10 inch - 10 spline). Trans will be a Clark 5 speed or a Spicer 5 speed. I will go with a Clark. You will love a Clark crazy shift pattern. 10 inch band brake on the backside of the trans. Your bellhousing trans bolt pattern will be typical Chevy / GM just as small trucks of the era. An SM420 four speed would bolt right in. If a Clark, maybe a 202V, but more likely a 205V or early 250V trans. 250V would be better, parts are still available. Clark of this vintage will be tagged driver's side, middle, near top edge.

Rearend will be a two speed, 8 point something low, 6 point something high. Appears to be cable operated. Your rearend will need no repair if water has not got in. The axle would have to be completely submerged for water to enter. Those last forever. Parts periodically appear on Ebay.

Vacuum fitting on your firewall, driver's side up high, indicates your brakes have a "hydrovac" unit, in essence, power brakes. Large unit, hard to see, under and between frame behind the cab, passenger side. Lack of a vacuum unit for shifting the rearend in the same location as your vacuum fittings suggests a cable operated rearend shifter.

Only took me two years to find a rebuild kit for a hydrovac. However, those units never go bad. Probably still works just fine.

A hydrovac indicates you will have twin wheel cylinders, two per wheel, 1.5 inch diameter. Shoes will around 4 inch by 14 inch each. No replacements around but easy to send in for relining. Brakes, when in good repair, awesome. Light touch on the pedal, great stopping power.

You have a hydraulic lift bed. Parts not too difficult to find. John Deere or Caterpillar parts will work if you can figure out right part numbers.

Rims, hard to see. Might be 19.5 inch or 20 inch. I would expect split rims if 20 inch. Your rims will be a Budd or Divco style, no modern replacements of the same size. Your rims are "hub centered" rather than "lug bolt" centered. Tires for both size rims are readily available, like Denman and others. You will know more once your truck is up out of the mud and cleaned off.

Only serious problem I see in your photos is no air cleaner. Odds are good water has entered, if not directly through condensation. If water has made its way through open intake valves, cylinder walls will be badly damaged. Might have to bore all the way to eighty-thousands, maximum limit pushing it. You can sleeve the cylinders or simply find another block which is less expensive. I would not attempt to turn over this engine. Head removal and inspection is called for.

Other problem is no gas tank cap. Trash can the gas tank, don't even think about using the tank. Replacements are cheap.

Do you have a good running chainsaw? Have fun!

Billyray

Forgot to add, Fatman, your cab parts are the same as small trucks. Gauges, steering wheel, glovebox, seat, glass, doors, all that is the same as small trucks. Your cab is no different than small trucks of the vintage years. This makes finding new or good used parts very easy. "Bowtie Bits & Pieces" even sells brand new replacement gauges, nice stuff.

Radiator, engine parts and clutch, same as small trucks, no problem there.

Your hood pieces, grille and all that, good luck! Doubtful you will find replacements. Never see those anywhere.

Headlight rims and buckets are the same as small trucks.

Same problem is true for rims, axle parts and brakes; few parts available. Only challenge is brake parts but those are available if you spend time looking.

On body work, if your hood and fenders are like my older GMC, you will need a sledge hammer to bang out dents! Very thick steel. Grille is the same, thick and strong.

An odd problem for you. This truck of yours runs a 5/8 - 3/4 inch wide fan belt. Actual is 5/8 inch but many label those a 3/4 inch wide belt and pulley. Should you switch to an alternator, you will need to buy an extra wide pulley. Easy to find, you will know when you see one; very odd looking.

A related problem is a packaged air conditioning system, such as Vintage Air. A compressor, like Sanden, will come with a 1/2 inch wide pulley. Wider is available but you must alert the supplier of your need. Better to change the a/c pulley than work at changing your crank pulley and water pump pulley.

All-in-all, Fatman, a great find and worthy of restoration. Your truck is extremely rare.

Billyray

His rims look to be dayton style. They're not that hard to find. Nice truck. I also had to use a chainsaw to remove 10 12 inch pines before I could get mine.

Well, I guess I'll have to get it out of there. I've got plenty of chainsaws and tractors to pull it out with! Just currently lacking in the money to do a full resto on anything. I've got an '86 F150 waiting in line to be restored/made into a mud bogger. Plus I'm only 20. Not exactly making big money right now. I need a place to store this thing too. Thanks for the info. On the front under the GMC in the grill it has a '450' badge. So I'm assuming it's a 450 ha. More info is appreciated if anyone has it. Especially tips on restoring it. I'll keep everyone posted on this.

The 450 was only offered with a 302. The cab is identical to a pickup. There is a filler between the cab and the butterfly hoods that give it the extra length. The butterfly hoods are unique to the 450 thru 600. The 550 and 600 would have an Olds V8 engine. The 630 would have a longer hood to accommodate the big bore inline. The 2 speed is probably an electric Eaton or it could be a Timken. It probably has a twin disc clutch which will not mate up with the SM420. The transmission would either be a Clark 205V or Clark 205V or VO which would be OD or a New Process 540 direct or possibly overdrive. If it hasn't been altered, the specs will be on the glove box door. Hydrovac brake parts are still readily available. As for the wheels, it is hard to tell from the picture, but they could be stud piloted discs or Dayton with 20" tires. Both of these are very common. As for the gas tank, it is highly likely that it either never had a seat tank or the seat tank was never used. Since these trucks got less than 5 miles to the gallon, they usually had larger tanks.

By the way, the cab and sheet metal is identical to a truck I owned in 1964. I have a 600 that I am restoring and a 450 for a parts truck.
http://picasaweb.google.com/crenwelgeoil/MyDocuments#5368146254965267442

Welcome to the bolt. Hope you can get it out soon

Kip from Livonia

Well I think I've found a place to store this thing. Me and a buddy of mine are going to try to pull it out of the swamp and haul it to a shop where we can take our time pulling it apart and try to put together a rough estimate of what it would cost to restore this thing. If it seems like it'll be way out of our budget we'll try to find someone who would like to buy it or use it as a parts truck...whichever one presents the best opportunity for the truck to actually be used and not scraped. If we do restore, it'll probably be a several year process. We both work 70+ hours a week and won't have much time to spend on the truck except for the winter months. Thanks for all the info, hopefully I'll be back looking for more help while tearing this thing apart!

I'm glad to hear you are pulling the old girl out of the swamp. Unless you have a particular interest in larger trucks, it will be an expensive ordeal to restore it. And of course it will never be a Saturday night cruiser. As for parts, 302's are always in demand, the electric 2 speed if it has one, would appeal to someone with a vacuum two speed and there are some people looking for front sheet metal for these old girls. I would like to see it restored, but if you decide to part it, I would possibly be interested in some of the front sheet metal parts. Send me a PM.