You're welcome. I'm happy to help. I have a little good news, bad news for you on this though. The 1993 Formula from what I understand used the T-56 Tremec which is the original variation of the same 6-speed being used in the Challenger and GM tends to use taller gearing in their transmissions than what Chrysler does so I'm not sure if that will resolve the issue from that standpoint. The good news is that I'm sure the Challenger has more sound deadening materials in it than your Firebird and the Hemi is most likely more refined than the 350/5.7L engine, so I doubt you will have as many problems with this engine. If it is anything like the 300C/Charger R/Ts I have driven, I doubt it will be an issue (plus I would tend to think that the VCT addition would help it a bit in the refinement department).