Cattle Dog Garage
The 128 variable was developed from 10’s of 1000’s of small block Chevy dyno pulls. In his video’s he alluded to other engines variables were estimated, at least that is what I got out of it. He said in the 318 mission impossible intake head porting video the SBM was close so another estimate.
I believe the only true way to spec a cam (his method) is from his and Stan Weiss IOP program which requires a thorough amount of engine data.
So the 128 SBC formula is a shortcut to use instead of the IOP program. For SBC only.
This is my take away on all of this.