The 1973 specs (transtar) I have show a 51" 74" and 84" cab. They also show cab raised 5" for Cummins VT903 NTC350 NTA370 and Detroit diesel 8v71T. Somewhere in the late 70s, 79 maybe they went to an 88" cab. Either way the the different wheelbases are clearly a myth. Hopefully Round 2 will bring either Transtar coe back. On a side note the 5" higher cab stayed permanently for the Transtar 2.