ill have to double check youtube for a 383 with a xe268.there is a 66 newyorker with a xe268 cam in a 7.2 compression 440 it has a nice lope to it.from what i understand a smaller engine will sound more radical with the same cam then a bigger engine would(for instance this same cam for a small block says 340 and 360 hp upgrde and it states will have a chop with a 318)