I'm not sure this will help. But in my younger days I took a 283 out of a 1960 Impala (side mounts)and put it in a 63 Impala 6 cyl.(side mounts). All I had to do was take the lower v8 mounts out of the 60 and bolt them in the 63. The mounts were bolted in on both and the holes were all their on both. I'm not sure if the trucks were the same.
