Well let's break it down here real quick.
Say it takes you about 12 hours total labor getting the front half of the truck parted out... as in cab, front clip, cooling system, engine/trans.
Now factor in the average prices for everything.
Most likely, that cab is non-A/C and is also a 2wd cab (trans tunnel is lower than a 4x4 cab, less desired). $500 if it has no rust holes.
Front clip... well all together and its shape, could bring in $300.
Doors - probably manual doors, $300 on a good day.
The whole interior... gauge cluster, dash pad, fingerbang bench, plain no-tilt auto steering column (73-83 had wipers and high beams on the dash/floor so it is not desired) ... all that together maybe $300.
Engine: If it's a 350, probably $150 running.
2wd TH400... $150 as well... nothing special.
Or just sell the thing for $1500 and not go through all that bullshit... plus an undesired frame with a flatbed on it sitting in your yard you probably will end up selling for $500 about 4 years later.