Have you driven the the truck with the T5 and the 4.55 rear end yet?
I ran a 235 with T5 with .72 overdrive and a 4.64 Nissan rear end and 28" tires and it was very driveable up to 70 MPH.
I switched to 215 85 R16 tires (31") and it is now all that I could ever dream of. 1st gear is more usable now (it was on the granny side with the 28" tires). When shifting into gears 2 through 5, the engine is right on the money of the optimal power band for this engine. No lugging at the begging of the shift, and no screaming engine when its time to shift into the next gear.
You might be pleasantly surprised with what you already have.
Carl


1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission