I have a 67 Dodge Stepside . How do I identify which slant 6 engine is in this truck? Also it was running when it was parked some 10 years ago. Is there any chance it will run?

Welcome on the board. Your engine is almost certainly a 225 -- the block casting number is cast into the manifold side of the block, and the engine ID number is stamped onto the top surface of the block on a ledge facing the sky, below the frontmost spark plug. You will likely have to scrape and clean away the grime and grease to read the stamped numbers. When you find them, post them and your engine can be identified.

If nothing catastrophic has happened (water into the engine, etc.) then it should run, though when engines sit for a long time you can get problems like stuck valves. As a precaution, you may want to remove the valve cover, squirt some good penetrating oil (PB Blaster or similar) onto each valve stem where it enters the guide, and give some sharp raps with a hammer on the valve end of each rocker arm. Make sure each valve actually moves. That way you reduce the risk of bending pushrods by cranking the engine with a stuck valve. If you can't free up any stuck valves this way, follow the more advanced procedure described here.

It will also be a good idea to service the oil pressure relief valve to make sure it's free, as described in these two threads: thread 1, thread 2.

Change the oil and filter. Try 10w30 oil and a good filter (NAPA Gold #1515 or Purolator #L30001; don't use Fram). Tune-up parts and technique suggestions in this thread. Once you get it running, the engine will need a valve adjustment.

There will likely be considerable gum in the carburetor. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download.

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Thanks! The truck is an hour away and we are going to put two days into getting it home next week. I'll post what I find. Im excited about getting this truck running. Thanks again.

When you get to the point of attempting to start the engine, make sure to use new, clean fuel.
On many stored vehicles I have started over the years, I disconnect the in-coming fuel line from the fuel pump, install a longer section of hose and run the added hose into a seperate can of fresh gas.
Drain, pull and clean the fuel tank / fuel lines before reconnecting to the fuel system.
DD