I thought it'd be fun to play with an NHC4 in a pickup truck. The NHC4 is just like 2/3 of the ancient 743 small cam. The 743 had fewer and smaller headbolts than the 855. I think I'd be more excited about completing the project if they made one that was 2/3 of a big cam.
I've probably got more seat time in 4BT powered vehicles than anyone else alive. I used to really like them, but now I could give a crap about 25 MPG. I won't settle for less than 6BT power and 19MPG is great with me. A healthy 12 valve is a lot of fun and still very economical. Rebuild one and it will pretty much last the rest of your life with a once a decade oil change.