The SAE 2 bellhousing for the 5.9 was one important reason why I decided to go with it. I considered the Big Cam, as I am familiar with them from having them in several semis and tractors here on my farm. After some thought, I didn't want to cut into the cab and have the motor laying beside me, as I want to keep it stock on the inside and not look like a race cockpit. That left me to decide between a 5.9 or a DT360. I chose the 5.9 due to availability and the aftermarket that caters to it. I bought one off of a friend, with relatively low mileage.
I am basing this build off of the "Klone Kong" truck that Jeff Dane made to resemble his original King Kong truck. He did a step-by-step build with it, and he used the original Caterpillar 3116 engine mated to the auto transmission. He had to cut the cab to fit it, and I didn't want to do that.
I have a 1978 F150 body that will be used for this project.
I appreciate all of your replies.