Yes a conv, I made sure to post my VIN: BH27NOB earlier in the thread to help clarify this issue of what is original to what cars, especially those missing a BCS where this info is recorded. Barry mentioned 'Cudas and R/T's for the 043 springs pictured and since my 383 4bbl is closely related to a 'Cuda in small ways I wanted to include for our discussion.

I think I mentioned the parts catalog listing a standard spring (043?), for which there is a HD counterpart (044?), and then there are the HD springs with their Extreme duty counterparts. Would like to help Moparclown get the right parts the first time around. What is your opinion for his 340 Challenger. Thanks Barry for setting me straight on the 340 going into only Challenger V8's.