BTW: if you haven't ported an IDI - you haven't lived!
That is a REALLY good article - and pretty much bang on with "standard practice" for many years since on pre-TDI 8 valve engines. BTW: if you haven't ported an IDI - you haven't lived! Freeing up the airflow (including exhaust) makes some fantastic power AND economy.
http://extrudehoneafm.com/automotive.htmlI just got back my PD150, perfect like a mirrorI sent them a new ahu head assy and a AAZ intake for a driver buildGB