my family truck updates and usability

[r.e.c.enthusiasts]

Alright, heres the deal.

Ive got a 69 chev fleetside 4 way coil springs 3 in the tree l6 250 6 lug drum brake every things manual and no power anything 2 wheel drive rust bucket of a fun truck full of memories that has been given to me from my father and we worked on it together since i was old enough to understand what tools were. Lol. We have taken it out to the mountains target practicing, dish sledding, and hunting. I love the feel of the truck vrs new trucks going through rocky areas in the off road beaten paths.

i dont have room for another truck and im not getting rid of this one.
But its limited. Poor mileage due to the gear box, and limited mountain play due to the 1 wheel drive.
I dont want to lift it, i dont want to lower it. I have a 402 that im gonna fuel inject and slap in there, but im gonna have a factory style muffler and resonator to keep it fairly quiet. So on that note.

I want a 4wd setup on this truck, i want front discs and would prefer to keep the 6 lug if i can. So what donor trucks should i look at and wielding is not a problem.