What do I have? 1950 GMC

[thetoddg]

My grandpa gave me his 1950 GMC 250 and I have some questions.

What I do know; The truck started life as a boom truck for an electric company. My grandpa traded a motorcycle for it in the early 1970's and turned it into a wood truck. He put the duallies on it and I don't know who extended the frame. The master cylinder went out in the late 1980's, so my grandpa parked it and it hasn't moved since. It ran when parked.

My questions.
What engine does it have? My grandpa replaced it at least once and claims to have the original size engine in it, so would it be a 270? And is there a way to tell the differences between the GMC inline 6's?

Does anyone recognize the rear end? If so, what kind of gearing ratios are possible? I kinda like the dually look and would like to put a different flat bed on it.

Is the 250 a 3/4 ton?

Any other information and/or advice would be greatly appreciated. Thanks.

[Highsider]

Welcome to the board! You are among helpful folks.

Work on getting a photo-host, like PhotoBucket, so we can see those photos.

[thetoddg]

Can you not see the images? They previewed fine for me.
I can redo the links so that they go straight to photo-bucket.

http://s1250.photobucket.com/user/th...?sort=3&page=1

[flashed]

Wow ,that looks like rust free .

[mr48chev]

I had to do some hunting on this one Still didn't find the usual info but a 250 is a 1 ton and it looks like the one ton came as a pickup with the 8 lug rims like the 3/4 tons had, the big truck rims front and rear with single wheels on the rear or the dual wheel version. http://www.oldgmctrucks.com/page0010.html

I'd think you are going to find out that your granddad swapped axles when he changed the truck around to be a wood hauler.

Cool truck with a real family history. I think I would do like you are planning and build a new bed while shortening the frame back to it's original stock length. A nice 8 or 9 foot flatbed would look real good with some stake racks that weren't too tall.

[Axe]

The rear axle will be a HO52 or 72, the 72 has a big adjustment bolt on the left side of the pumpkin for ring gear deflection. Not sure about the HO52's but the 72's have 4.57,5.14 and I think 6.17 gears. I'm not sure about the last gear but the other I'm sure of because I have one with each. Some even come with Detroit lockers, they are good axles.

[thetoddg]

Originally Posted by Axe

The rear axle will be a HO52 or 72, the 72 has a big adjustment bolt on the left side of the pumpkin for ring gear deflection. Not sure about the HO52's but the 72's have 4.57,5.14 and I think 6.17 gears. I'm not sure about the last gear but the other I'm sure of because I have one with each. Some even come with Detroit lockers, they are good axles.

Thanks for the info. I will try to get under it this week for more pics.
Which gears would make for the best cruising?

[b.sharp]

None of the above gears will be good for cruising, unless you are cruising at 45mph. These were farm trucks meant to be used on the farm or haul around local towns. They will pull a house down but very few would do 60mph without great strain. It all depends on what you want to do with your truck as to what rear end or any other modification you do to it. Great looking truck and great family history.

[eagleuh1]

If you could go with a 4l60 or 700R4 with overdrive, the 4.57 isn't too bad. I did end up swapping to a 3.54 Dana 60 though in mine. Nice truck.