My serial number is 8305 S 221570. The SM indicates that a letter S following the serial number prefix indicates the engine is equipped with an exhaust emission control system, but I don’t have one. I also don’t have an oil bath air cleaner (I have an edelbrock air filter). Would the EECS have been removed when the oil air bath cleaner was swapped out, or am I misunderstanding the meaning of the “S” on my S/N? Thanks.