Had tah be dealer installed. '60+'61 long cross rams, '62 2X4's north 'n south '63+'64 short cross rams. Those 5 yearz for dual quadz and never before or after from the factory. Oh, and 4 or 5 sets of water heated short cross rams(as opposed to normally exhaust heated) supplied to racers in '62 only. Granatelli, Fobble, and ah couple otherz, Jer