Hi Swami,
I have a 3.07 rear end, a .86 fifth gear and 27 inch diameter tires and it works great. Nice, quiet and efficient. At 65 I'm around 2100 rpm and the engine is just humming. If you're using a 235 made between 1959 and the end of production in 1962, you get a bonus. You get the camshaft that produced maximum torque at the lowest rpm...that being 217 at 2000 rpm. The 1958 235 required 20% more rpm to hit max torque which was only 215. And if you look at the torque curve for 1959-1962 you'll see it is a nice flat line starting around 1600 rpm going all the way over to 2500 rpm before it starts the decline. That's an impressive line, by the way.
Here is something for you to consider: When your truck was made the engineers wanted it to have an overall first gear ratio of 12.08. That's 4.11 x 2.94 (your stock 3 speed first gear ratio) and they knew what they were doing...it works well for the engine power to weight and ratios like that were used in almost all 1/2 ton pickups. That overall ratio will let you put 1000 pounds of stuff in the bed and drive around without burning out your clutch. It will also let you travel through a city intersection without having to shift to second. If you use a 3.90 rear end and a 3.76 first gear ratio you'll have an overall first gear ratio of 14.66. That's over 20% higher and what that extra ratio means is you'll be needing to shift from first to second sooner than you might enjoy, second to third a little sooner and on and on. Not a condemnation but just something for you to think about before you pull the trigger. The stock overall ratios were 12.08 (first gear), 6.90 (second gear) and 4.11 (third gear). Your ratios will be 14.66 (first), 8.50 (second), 5.54 (third), 3.90 (fourth) and 2.80 (fifth). First and second gears are where I think you may not enjoy that ratio chain as much. May not be a concern in Prineville but in a city like Dallas, that much shifting all the time can get old and I think you might be looking for something that would let your engine wind out more slowly and have you shifting less frequently. Good luck no matter what you choose!
