I found two used "454" flywheels, well the guy says they're for a 454. He said one is for a 11' clutch and one is for a 12" clutch. I know I need 168 teeth on the ring gear for an aluminum bellhousing, but how do I tell if these are for an ext. balanced 454 and not a 350- etc.? Anyone have info or pics of what I need to look for?