Indy Head information

Need help on identifying a set of heads that I have. These are Indy heads with the number 3327 and 308054 on the heads. I need to know if these are the SR heads? I'm using 2" TTI headers now but from I have read I need to use the 2 1/8" TTI step headers with and different K member for a 71 Dart. I already purchased Hemi Denny front end so I think I got that problem solved.