Inliners International Forums General Discussion Drive Train Torque tubes . . . how strong are they?

I have a '38 Chevy 1/2 ton that has a beater 235 in it that has a rod knock. I have a low mile 261 that I am considering dropping in place and running. Might add Fenton headers and dual intake. Will the rearend and tranny take the torque of the bigger six? Should I change over to late model tranny and open driveline rearend?