[B. W.]

If you want to keep the 420 you could swap the 221 for a Dodge divorced 205. Not a direct bolt in but close enough it wouldn't take too much work & probably the cheapest option. Not sure of what years Dodge ran them but I know they were in the early 70's trucks. Swapping to the 465/205 is also a great plan(IMO). You could also do the NV4500 / 205, the overdrive would be nice! (most expensive option)