My buddy and I have done two, one '51 5 window pickup using a 305 TPI/700R4, the other a '53 panel with 350TBI/4L60e. Used a Speedway or Classic Performance Parts engine crossmember. This stiffens the frame enough for regular driving, dunno about towing, it also as well has an automatic type rear crossmember. Both trucks run great, look good, start and run great when cold and with the AC on, and keep up with modern traffic on any road.
