1941 Pickup Drive Train

[cwottinger]

So i just purchased a 1941 Ford Pickup. The flathead motor appears to be locked up so I was thinking about putting a 327 small block in it. I realize i will have to adjust the firewall in order to do so. I plan to pair it with an automatic transmission and replace the original rear end or axel on the truck. I am curious if others have done something similar? I was wondering if anyone has replaced the rear axel with something more modern and what would possibly be a somewhat perfect fit in the truck? Any advice is much appriciated.