You've got a lot of choices. Me personally, if I had a truck with no engine or a blown engine, I'd be looking to go diesel. However, you can have a good F or 2F for much cheaper and it would be on the road quicker most likely. Check out the parts for sale section here on Mud and you'll find something in due time. Not sure where you are, but adding that to your signature might bring some possible engines in your locale. Good luck!
I just blew the original F engine in my '68 (courtesy of the PO messing up a rebuild) and dropped in a 2F replacement. Cost me $250 for the engine, $1800 for the rebuild and 1/2 day labor with help from my bro. Literally after 4 hours of installation/assembly I turned the key and she fired right up. Felt like a fantastic choice as I was able to reuse all the original F engine anicallary components, it made for an easy bolt-in replacement, and was pretty inexpensive.