2.73 gears are a bit high for a 235 and an automatic. 3.90 to 4.11 gears would work well with a 700R4 and a 235. Is your 54 already open driveline? If so, the stock rear will be perfect for a 700R4.
Now what transmission is best depends a lot on how you will use your truck and your budget. Personally I like having Manual transmissions in a truck, not automatics, so my dream transmission is clearly different from yours.
Trucks and hotrods like low gears. 2.73 gears are very high on the economy side. As economy gears, acceleration will be poor at all around, and don't even think about towing anything. 3.90 gears will pull a load and accelerate quickly, but might cost you in economy. If you were running a transmission with a 1:1 final drive, the above would be true.
The 700R4 is an Overdrive transmission, with the final drive ratio being around 0.7:1 Using this transmission with 3.90 gears would give you all the benefits of the low gearing for acceleration, torque and grunt, but in OD it will also give you the economy. The 3.90 gears will affectively be 2.73 gears in OD. This would be a win/win situation.
2.73 gears and a 700R4 would not be a very useful or economical setup.
