Yes and no...........the front end will bolt up, but the rear won't.
On the front end - the '79 crossmember will bolt to your '66; you will only need to drill two holes and wallow out two holes on each side. You will need to drill holes for the '79 idler arm to attach to your '66 frame as well; they are mounted in opposite orientations (the '66 is leaned fwd, and the '79 is leaning aft).
As far as the rearend, the mounting between the two years is totally different - sway arms on the '66, leafs on the '79. I used a '75 parts truck; I first took all the brackets off of the '75 and ground it smooth, then made a jig for the '64 rear so as to locate all the connections, carefully washed the mounting hardware off with a torch, then put the '75 rearend I used in the jig, and welded all the mounting hardware from the '64 onto the '75 rear. Worked great.
......I am still working on a tech tip for this........hopefully this year!!
