Just out of curiosity what are the measured volumes for the intake and exhaust runners, and the chamber for 416 heads and 906 Vortecs?
I just measured a few on the sets I've ported and I came out around 173cc's for the intake runner on the 416's and 58cc chambers (cleaned up but not "polished").
My intake runners thus far on the Vortec's are around 178cc's.
Have yet to measure them all or even one exhaust runner.
Both sets of heads are running 1.94/1.5 valves. I also have a set of Vortecs I did that have 2.02/1.6 valves. I did not measure those yet either.
I was suprised at how high the Vortecs were considering I didn't do any major work, cleaned it all up some and just did the basics.