I've got a 67 C-10 that handles much better than my 68 Camaro! Of course, it's been lowered 4"in the front and 5" in the back and has power steering to boot. Also, about 4 years ago I installed a 77 C-10 front end on it for the disc brakes. I prefer the rubber bushings as opposed to the screw in control arm bushings. Not a difference in terms of handling better, it's just that I prefer rubber for its installation ease and service life.
Btw, yes, the later year FE will bolt right up with an enlargement of one hole on each side of the crossmember. I chose to leave the original crossmember in.
Not sure if I've helped out with your initial question though.
