"Challenger 600 Specifications"
"Challenger 601-1A: Featured General Electric (GE) CF34-3A engines with 40.7 kN (4,145 kgp / 9,140 lbf) thrust each. Initial flight was on 10 April 1982, with 66 built into 1987."
"Challenger 601-3A: Featured GE CF34-3A engines that could operate at higher temperatures, and Honeywell digital avionics. Initial flight was on 28 September 1986, with 134 built into 1993."
"Challenger 601-3R: Same as 601-3A, but with fuel tank in extended tail; 59 were built into 1996."
In contrast to his early Lear Jet designs, whose tight cabins were predicated on a philosophy of short leg lengths and high speed at minimal cost, Bill Lear drew his Lear Star 600 with a spacious cabin in which passengers could bask in comfort for transcontinental stage lengths.