Again, I think the /6 here is the way to go, but if it had a say 318 (there's a zillion of them) I'd voted for a big block possibly? I know a guy out in Missouri, who has a #'s 1970 /6 Charger and if I remember correctly it's a 500, funny how Ma Mopar "corrupted" that name plate, but it is one rare car as far as prodution numbers are concerned. The car is a mess and needs a total resto, his plans............keep her just the way she was. By the way, the same guy has a 70 Charger R/T too, he thinks it will be super cool one day seeing them parked side by side at shows.