I have a 261 bored .030, split exhaust manifold, a 4 speed manual overdrive (MYA6), and 3.50 gears in a Ford 9" diff. I am running a Carter Yf carb from a 235, which need to be bigger. This combo will run as fast as I want to drive (80+), although the carb needs to be bigger. The engine turns around 2000 rpm at 65 mph and I never have to downshift in normal highway operation.
This was a pretty straightforward swap and works well.
