thanks.
The t-34 was ordered when the vehicle was purchased. It was ordered in March, I took delivery in June 1973 -- thought the delay was for the 5 speed, but I have since learned there was also a "shortage" of 392s.
I "picked" the rear axle ratio based on the rpm I wanted to run in od on the freeway -- I figured out the formula and ran the "numbers" for the 3 axle ratios (3.54, 3.73, 4.10). 3.73 equaled 75 mph @ 2800 rpm in od.
The current tires - michelin 245/75x16 ltx m/s - are a little taller (approx 1 1/2") @ 30.7 than the original goodyear nylon 9.50x16.5.
The IH salesman would let you "walk thru" the option book when you special ordered a vehicle, so I also got (ordered) the 12x3 front brake shoes (probably part of the towing / camper special packages).