[blackhawk 06-08]

the car originally had a 409 ci motor. it still has the 409 emblems but has a 350 4 bolt main in it now. the car hasn't been restored yet but is in really good condition. it has a very little cancer on quarter panels and a little on the hood. it also has a muncie 4 speed tranny and car runs. other than that, body is straight. is the car worth $3500 without the 409 and with a 350? if so where can i find a 409 to try to keep it as original as possible? i would greatly appreciate help on this matter!