Wow that is really a sweet Roadrunner. 121 mph is enough for 10.90's. You should be able to get the 60's in the 1.50 to 1.60 area. My best 60 is 1.50 at 10.76 but I have run 10.92 with a 1.62 sixty spinning but that was at 124 mph. I think that Hemi has a good bit more in it. Work on the 60's and the tune and I think you will be running easy 10's. Good luck , Ron