906 Vortec heads

[Dirtwiz]

I've just bought a set of the 906's and want them to perform at their utmost. I've called several different engine builders and get a different response from each of them Some say port--others say to stay out of the port. Some say flat cut them .060 while again others have told me to have the water ports on the spark plug side welded (or pinned) and angle mill the snot out of them. Then I get one who says to put 2.02 and 1.6 valves in...And when you start talking about camshafts that compliment these heads---they really have different opinions. Internet search says they perform best ay 32 degrees of timing while one guru told me 36.
lets get to the bare bones about these cylinder heads---who has experience with them? What worked and what didn't work for you?
Thanks!!

[Dirtwiz]

Guess I ain't in the click...

[Dirtwiz]

Thanks Jeff

[Graff Spee]

Do not port them! Taper the guide boss not getting closer than .060 to the valve stem. do clean up in bowl area but do not change just clean up! 2.02 and 1.6 valves work great in these heads. A nice 3 angle valve job is good. radius or blend in the 60 degree cut as it goes into the port. Valve guide clearance is also very critical to making power. Gasket match the intake runners not going more than an inch into the port. A 30 degree back cut on the valves is good. Find someone with a single point machine to do the head work and you will be good. We make the best power at close to 35 degrees of total advance.This is just basic stuff that works for us all the time. I hoped that I helped. You can cut the pockets for 1.550 springs with no issues. studs and guide plates just like normal. we run over .650 lift with a roller cam couple championships already on this engine.