Need some advice

[75chev4x4]

Hey guys I'm sure a few have seen my posts before about the steering on my 75 k20, but I'm kinda at a loss right now with what to do with this truck. I need some advice on a project point of view on this thing. I have had it for about 5 years now and done lots of work to it about $8k worth and it has steered bad from day one. Anyway aside from all the money and time I have put into this truck I never get to drive it or use it much except short trips in town because of how horrible it usually drives. I say usually because sometimes it can be ok and sometimes like tonight it is just down right scary to drive. I have replaced EVERYTHING in the front end of this truck: new steering box, sway bar bushings, steering box brace(no cracks around frame), borgeson steering shaft, new tie rods, new center link, drop pitman arm(2" lift), new drag link, new ball joints, wheel bearings repacked, tires are good and have had them balanced many times. I even found an old school alignment shop and after taking the truck there it drove the best it ever had which was ok, but is now back to scary again. I'm to the point where I don't have anything else that I know of that will fix the way it drives; have to correct it back and forth to go straight and then it will kinda dart if you correct it wrong and scare you to death, it just kinda wonders. You have to pay close attention while driving it because your not sure how it will react to the next bump or corner. Anyone had a project like this? Is it best to stop chasing it and sell it or leave it alone for a few years or... ? I really love these trucks and I would almost like to just go buy a 2wd(thinking it would handle better than my 4wd) of this generation and swap all my stuff over to it but not sure how the 2wd ones drive either. Almost thinking of going and test driving one or two similar to mine on craigslist and seeing if its just mine that drives this way or what? OK, well any advice would be nice guys, hope this didn't sound like a "poor me" rant but I'm frustrated with this thing, thanks!