I'm going through the same with my Duster. I have pulled the "race motor" (9.80/135) and built a pump gas 383 (11.20/118) . I put torque thrusts-drag radials, carpet and a bench seat in it, probably going to swap out the 4.56 for 4.11's. The good part for me is that I am only about 25 minutes from Beech Bend which has a low key street based series they run on Saturday night that fixes my race itch pretty nicely as it is a 3-4 hour commitment. I'm still trailering it for now but I am working toward being able to drive it to the track-4.56's with an 8 gallon cell has a pretty limited range. My biggest issue is exhaust as with fenderwell headers it is difficult finding a solution that keeps it quiet. A nine second N/A car is pretty limited on where it can be used, an 11-12 second car can have a few more options. I keep thinking I want to put a small block 6 speed combo in it to truly make it street/strip and more fun to drive. I've had the car nearly 20 years now and I am finishing up the 4th engine for it. I really want a 63-65 B body post (this is where the race motor is going), but in all reality I can't imagine the Duster not being in the shop as it is an ongoing father son project so I will likely never sell it but I do want more use out of it.

I vote keep it, detune or build less HP. There is something nice about having a car that you know everything about and in the end, I think you would regret selling it.