Even with a 318, you need to add an inward bump to the oil pan for the V-8 steering cross-link to clear the oil pan at one limit of travel. I think if you could find a 64-66 273 pan, it would fit and have that depression. As mentioned, a slant-six cross-link doesn't drop as much and won't clear the pan, but some say many 1966 slants came w/ the V-8 link. "Drag link" sounds more like the "drag strut" which goes from the lower control arm forward to the radiator support. Some people have used the transmission that comes w/ the Magnum engine, to get a 4th overdrive gear, plus lock-up converter for better cruising. But, they had to rework the whole transmission tunnel to fit.
