I regularly played with a Duster 340 on my way to work in my '65 with a 68 340 in it. Id beat him every time to the point that he wouldnt even race me anymore. Mind you this was on a resi blvd and we'd take it up to about 60 and then let off but I'd beat him to 60-70 by about 3 car lengths every time. 3.55 SG 7.25 rear too! His 340 looked 100% stock, most likely an auto like mine. I beat a buddy in a Camaro with a 6.6 motor too. He had that weird diagonal carb mount Edelbrock torker intake.