Just a thought, But how would a 24v head work on a first gen truck. In the thoughts of performance, the four valves per cylinder flow much better than the 2 counterpart. Only thing I'm not sure of is how lines would work and if the increased flow would benefit us and the VE could keep it fueled etc and what it would do to egts.
Wrong piston design for the 24v injectors so you'd need to change them, custom injectors, custom lines and a few other things. What your trying to gain is not worth the effort unless this is an all out high hp build and even then a 12v with machining and runner intake can and will be more than adequate. I'd rather spend money elsewhere if I was you.
Oh and to flowing better than 2 valves. Not by as much as you think it would also I have a highly worked over 12v head on my puller that will flat out flow any 24v or is comparable to a full out 24v one.
valve-train drive conversion would also be .... involved.... I presume. You want to have too many valves, get one that was already made with too many valves, and don't use a VE . Go to a P . Or do like that other guy and port your existing properly-numbered-heads really well.