Nope, I'm saying exactly what I meant. DV's formula was devised for modified factory SBC heads & similar, with adjustments to the formula already noted by another poster above, that's what I'm saying.
That also would be modified for cast exhaust mannys vs headers, restrictive exhaust vs open, etc.
If You plug that formula in, many of Mopar's PurpleShafts track pretty close to it, & I'm certain Shepard & Co. did enough R&D of their own.
