sentences:  The total number built was 139, plus one development chassis.The Falcon was closely derived from the Dennis Dominator, the front half of the chassis being identical.The original horizontal-engined Falcon H had a layout recalling that of the Bristol RE with the longitudinally-mounted Gardner engine driving forward above the Dennis-built portal rear axle to a Voith gearbox and reversing unit which then took drive rearward into the driving-head of the axle.