I didn't revisit the video, however, I think the 906 heads were not prepped but cut just a little to make the compression even.
i just dug up a Mopar Muscle build by Dave Young from 2012
383,built to 10.1 compression ratio
mildly ported 906 heads,comp .502/512 cam,roller rockers,victor intake
dynoed 360 hp and 380 torque
