Did you then, and do you now, Actually believe this to be correct?
I have heard many "theories" over the years, none quite as stone age as this though. Most thought that while porting they wanted to keep port velocities high, so ported, but not Over ported.
You're saying leave the intake side untouched or just cleaned up with stock vales and all?
IF this is what you have done, I think we just found your slow spool issue