I think all the members try to help in their own way so take it all in and make your own informed decision. Jerry's comment about needing torque has merit. The old truck has the aerodynamics of a billboard travelling down a highway. At highway speeds (60-65 mph) a 235 with a 3-speed overdrive (4.11 X 0.70 = 2.87 final gear equivalent) can/may use up more gasoline than a 261 with the same transmission at the same speed.
Mr. Google tells me that to "cruise around" means to move or travel slowly around an area, usually without a specific purpose but with the hope of finding something interesting. A lot of people do this quite easily in a stock truck.
Factor in that old, well-used rear axles tend to have worn ring and pinion gears, bearings and seals. This can become a big $$ headache. Since you are going the T5 route you may want to ponder the 4X4 S10 Blazer rear axle.
