Hi,
I have a '78 block in my 68 mustang with the original 68 balancer and pulley, so I would asume you could do the oppositte with a later balancer on an earlier engine. Just make sure that they have the same number of v-grooves. Most late models will have 2 grooves (for power steering or a/c). Most pre-68 6 cylinders only had 1v-groove. (Don't confuse the balancer grooves with the smaller pulley groove(s)).
Hope this helps
Dan
68 200 under construction
268 cam
header
1980 250 head
petronix
