Is there any difference between the mounting locations (chassis and diff) and actual radius arms that were fitted to early twin cams with the early shock mounts Versus the later more upright shocks. Specifically is the diff mounting point for the radius arm, the arms themselves or the chassis mount points.
Also any idea where to source the rubbers for the radius arms?
 

On late Mk1's the radius arms were angled in towards the car centre whereas on early Mk1's the arms were more parallel to the car centreline, so the arms are not the same and the rear mounts on the diff housings would have to be at different points. I believe the front mounting points would be the same early or late. The front mount early or late uses a metallastic type bush part No. 118E 55553 A which is a MK1 Cortina part No. also used on Mk2 Cortinas. The rear bush early or late part No. 69EB 3063 AB is the same bush used at the inner end of front track arms.