I’m wanting to do the same thing. I received a set of “free” CUCVs a 1008 and 1009 from a good friend. both need drive trains . The 1009 has no engine or trans. It may be easier to just put in a small block or maybe a 454
I would never sell them so I’ve got to do something with them.
The good news is junkyards are full of parts that can be made to work. My only issue with the CUCV is how slow she is on the busy roads. Sounds like you got an open platform to build a cool truck.
I did find something really interesting. DIYAUTOTUNE.com
This site helps you build controllers and has already made transmission controllers for the 4l80e. Which can be tuned if needed.
I think i read the articles right where you can also add on an engine controller. Which is super cool and also educational with support in the USA.
But, for right now i have a SBC 350 with headers i can drop in with the 4l80e swap. This might be the most cost effective for me currently. Definitely will be grabbing LS 4.8 or 5.3L parts at the junkyard for future use. I counted 26 trucks at the local junk yard. Holy molly they are rot boxes up here in NY.
Junkyards for me are like dropping a kid off in a candy store. Next thing you know i will stubble on a descent 6.0L. lol
Have a great day
Matt