The Hellcat uses a 54mm bore engine. I think this one would work,
https://www.ebay.com/itm/CYLINDER-TO...ty!90603!US!-1
This one seems like a really good deal but they say "not in stock coming soon" you could call or email them and ask when it will be in stock.
http://www.motopartsmax.com/index.ph...90/cPath/21_85