1957 GMC 100 - 270 Engine

First thanks for having this forum and thanks in advance for any advice you can give.

and ..... If you have a 270 I could be interested in buying it.

I have a 57 GMC 100 step side (originally a 3 on the tree) that a kid back in the 90's transplanted a 230 and Turbo Hydromatic 350 into by torching the cross member out and adding some modified motor mounts. I would like to get this rig back to close to original and use it as a driver, vanity truck for around my area. I've managed to find a cross member, and a 3 speed and now I need to get a 270. These are from a parts dealer in Marysville, Washington. I'm dreaming of having a numbers correct engine but have found a 1953 270 that I can up pick up for a few hundred. Will this fit my truck? It came out of a fire truck. supposed to run.

I've used this page to research casting numbers http://www.oldgmctrucks.com/Photos/GMC_Numbers.htm
Now I have what is a simple question about casting numbers... Are the numbers listed in the table the starting numbers and what falls after that and before the next years designation valid? In other words will the number be different but be between the two? See these examples:
The list calls out these for 1957 GMC 270 Engine Casting #'s but they cross multiple years
2404929
2324003


I've taken this 2136477 to be a 1953

Someone else had one with this number - 248260112.... Is this a matching numbers correct for my rig?

Thanks again,
David

 

the first numbers stamped next to the dist on a pad denote engine size. 228 or 248 & 270 and every once in a while a 302. I have a 248 in my hoard. the last you mentioned is likely a 248. the GMC 6 is longer than a chevy engine. you need the correct GMC radiator to make everything work properly.

 

Military blocks are different in the way they mount so the holes on the side of the block are not all the same.There were military 270's as well as the more common 302.
I'm guessing a 55-59 Chevrolet 6 bellhousing will fit the cross mount you have found. Should be ez to find.
Some front mounts look like saddles which have 2 bolts on either side right at the front of the block and others mount to the plate which goes on the engine first before the cam goes in. That one is more common on earlier models.
Just thing to look at. I would advertise for someone doing a V-8 swap into a 55-59 for the correct parts. Good Luck

 

Thanks all for the info. It's been a while but I've been gotten a couple old engines blocks and getting closer to getting to the point of putting it all together. I'm still searching for that correct numbers engine that's good enough to use. Retirement is coming soon so I'll have more time.
David

 

Wow! I got lucky and picked up a running 270 that was being used in a 1954 GMC step side. They wanted a small block so I bought the 270.
I'll need bell housing to mate up to the 3 speed I have to get back to 3 on the tree. I've already picked up a rear cross member to replace the one taken out with a cutting torch and have a clutch pedal to replace the one that was removed. Now to find some time.....