428 Super Cobra JetThe 428 Super Cobra Jet used the same top end as the 428 Cobra Jet but the crankshaft, connecting rods, and pistons are different. Cast high-performance pistons, a nodular iron crankshaft casting # 1UA was used as well as heavier 427 "Le Mans" connecting rods with capscrews instead of bolts for greater durability. The heavier connecting rods and the removal of the centre counterweight on the crankshaft 1UA, required an external weight on the snout of the crankshaft for balancing. An engine oil cooler was standard equipment with the Drag Pack and 3.9 or 4.3 rear end gear ratios. This engine was also underrated at 335 brake horsepower (250 kW). Since the 428 SCJ was based on the 428 CJ here is the 428 CJ data below. 428 Cobra JetThe 428 Cobra Jet, launched in April 1968, was a version of the 428 FE engine built for performance rather than cruising smoothness. The 428 Cobra Jet could be made on a regular production line, not requiring the exacting tolerances required by the 427. The 428CJ used special cylinder head casting # C8OE-6090-N. This casting had larger intake ports and valves than production FE. The Cobra Jet used a strengthened version of the 428 block with an extra main bearing webbing and thicker main caps than the standard block. The CJ used heavier connecting rods with a 13/32 rod bolt and a nodular iron crankshaft casting # 1UB. The engine was rated at 335 horsepower (250 kW) at 5200 rpm, but true output approached 410 horsepower, particularly in engines equipped with a functional hood scoop and unrestricted cold air induction. The low rating reflected management concerns with rapidly escalating insurance surcharges, which were hurting sales of high-powered muscle cars. The low rating also inspired the NHRA to factor Cobra Jet mustangs to 360 horsepower for drag racing match ups.
|