Brett Miller was able so have some of these cast differently, I am not exactly sure what all is different but there is only 6 or 8 sets out there. That duster has one of the sets. Or at least that is what he told my Dad on drag week last year.
I found a Stainless Works video interview Trunkett did. He mentions the engine and the heads and there are some views of them. He does say they are Brett Miller Victors on about 440 cubic inches. Very cool.