Thanks for the reply Wrench Fetcher !
I did some research on the block number. I miss-read the number.. The last 2 numbers are TA, which means it's a jobmaster 261 cubic inch engine. My vin number matches the number on my title, and I'm thinking that this engine is more than likely the motor that came with the truck originally. The guy that had the truck before me lives the next town over to the west from me, he's had it since 1979.
I did pour diesel fuel into the engine this morning. It's not going to solve the problem, but it's not going to hurt anything either.
Time to take the front clip off. I'll be able to get at the engine a heck of a lot easier that way. Is it a cracked head or just a blown gasket.. I won't know until I take it apart..

http://s56.photobucket.com/albums/g178/reroy55/?sc=1&addtype=local