Does anyone know what the broadcast code YP (for front coil springs) mean. What cars used them?

Thanks

All the following 69 Camaros:

A 6 cylinder coupe with a heavy duty suspension and 195 to 262 lbs of options on the front end.
An 8 cylinder coupe with JL8 and heavy duty suspension and 181 to 262 lbs of options on the front end.
An 8 cylinder coupe with L48 or L65 engine, HD suspension and 181 to 262 lbs of options on the front end.
A Z28 or 8 cylinder convertible with HD suspension and 99 to 180 lbs of options on the front end.
A big block coupe with standard front suspension and 181 to 262 lbs of options on the front end.
A big block convertible with standard front suspension and 99 to 180 lbs of options on the front end.