1972 duster 340 value / worth ?

i am looking at acquiring a 72 Duster H code car . it has a demon front end on it. it currently has a 340 4 speed idk if it’s numbers matching engine or not. car runs and drives good , paint is faded non original yellow could use new paint but the only rust is minor on the bottom of rear quarter panels . everything else is solid no bondo. interior is clean but the car was built for bracket racing supposedly. it is mini tubbed and has a cage going through the back seat . what’s a rough estimate on the cars worth ?