There's a common misconception that the 5th character in the Vehicle Identification Number (VIN) can be used to determine if a car is equipped with a Cobra Jet (CJ) or Super Cobra Jet (SCJ) engine. The myth is that Q-codes are CJs and R-codes are SCJs. In truth, these codes identify the type of induction system installed during factory assembly. 1969 - 1970 428 CJs and SCJs that were equipped with standard air cleaners are identified by the letter "Q". Ram air induction is identified by the letter "R". The axle code on the door tag generally determines whether or not the engine is a CJ or SCJ.