You didn't state auto or stick, so here goes.
Trucks in the early 60s were supplied with an adaptor to place the V8 727 behind the six, but it doesn't work the other way around. The average six cylinder 904 wouldn't cut it behind anything but the most mundane of V8s anyway, even if it did bolt up.
A833s are a different story and all will bolt up and be strong enough for almost any V8 provided the front bearing retainer and V8 bell housing diameter match up, or a spacer is used to allow a smaller bearing retainer to center up in a larger diameter bell housing opening.
Mopar Performance re-released virtually all the different sizes of bearing retainers recently and could simplify bell housing match ups (depending on front bearing size). Good luck finding a dealer left to sell you one now that Obama Motors has taken over, best bet would be to call Jamie Passon or one of the other suppliers specializing in Mopar manual trans parts.
