What Are The Differences? The 428 SCJ was first introduced during the l969 model year Buyers who selected either of the optional 3 91: or 4.30:1 rear end gear ratios got more than just an opti al exie'retio! Ordering either of these axle ratio options; eotoonatieeily triggered a few other upgrades as well. including the 428 Super Cobra. Jet engine an external :- '- i '- oil cooler mounted In front of the radiator and relocation of the drivers eide horn to the passenger side of the radiator core support to make room for the oil cooler ' Starting- n February 1969 this oomplete package