identifying a straight 6 engine

I bought a GMC 1953 sidestep 1/2 ton pickup 3 years ago. Does anyone know where I can send photos of the engine as it is not the original engine, so that I can get some help to identify it. As I'm in the UK help is not easily available.
Thanks.
Andy  

Do a little post-searching, here. I'd bet you can find the information you need.  
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1949 Chevy 1 1/2ton, home-built hydraulic wrecker.  Rustoleum industrial black, with flames.  Flamethrowers out 5" dual stacks.
1962 Chevy C-20, 402BB, 4-speed, 3.90 positrack. Hauls my camper.... among other things.

Look on the right side of the engine behind the distributor. There should be numbers cast in the block. Stamped numbers are not what you're looking for. GMC engines start with 21, 23, 24, 37(seven digits)and 38. Chevy starts with 35, 36, 37(five digits), 38, 39 and 40.
GMC Engines will be seven numbers, including the two listed. Chevrolet engines will be seven numbers starting with those listed above. If the number starts with 37, it will be only five digits. When you find the casting number, post it and someone will help identify it.
Good Luck
Buffalo
Keeping 'em inline since '53  

Thanks for your reply. I have found a number on it, 473483, I have got a photo, is it possible to send one to this site? It's great to get some feedback, much appreciated.
Knocker  

473483 sounds like a 250 Cu.In. with the integral head. Check the engine if it doesn't have head bolts, it's the integral head model.
Hope this helps,
Buffalotrux
Keeping 'em inline since '53  

WHAT!?! Tell me you aren't serious!  No head bolts?  I don't know whether to laugh or swear.  

An integrated head 250 has head bolts just like any other.  The 'integrated' part is the intake manifold being part of the head.

IIRC, a lot of integrated heads were replaced with earlier head/manifolds, when they cracked, as was a common failure.  
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1949 Chevy 1 1/2ton, home-built hydraulic wrecker.  Rustoleum industrial black, with flames.  Flamethrowers out 5" dual stacks.
1962 Chevy C-20, 402BB, 4-speed, 3.90 positrack. Hauls my camper.... among other things.

knocker777:
Thanks for your reply. I have found a number on it, 473483, I have got a photo, is it possible to send one to this site? It's great to get some feedback, much appreciated.
Knocker

Here is another post that should help you out with posting your picture. If you have any difficulty let me know.

http://forums.classictrucks.com/70/7616913/open-forum/pictures/index.html  

i have a straight six and i dont know what model it is. it is 473483  

so i have a engine that has cast numbers 3350817 o gmc what engine is this 230 250? it is currently in a 64 chevy c10  

With all the request out there for identifying engines are there any websites or tools that anyone knows of that might help?