They did not make the best use of the resources they have. I watched this build many times and there is no mention of cylinder head work......they really seemed indifferent to the Slant 6.
They could of done more but it's probably close to most peoples hopped up /6. Not too many go to effort of porting not even in a lot of V8 builds and even a healthy bump in cr is lucky to give 10% hp increase.
You got to have other reasons to build a NA /6 power isn't one of them.
