I started a series on porting the 906 big block head and I've done some work on a port trying to emulate what I did back in 2008. While doing this I was on the hunt for that big number but in the process found some very interesting things and I want to talk about that.
.100-.400 lift
What got me thinking about this was last night I watched Eric weingartner go over and give his opinion of a CNC ported set of 906 heads. Eric spoke of them gave his opinion showed the flow numbers and then compared them against some of his own which he had I believe three flow sheets for back when he was taking iron work. The thing he doesn't mention 'but if you use your eyeballs'..you can see he uses a way bigger valve @ 2.25, while the cnc 906 is at 2.14. His numbers are pretty average and don't do much better than the CNC had with the smaller valve so that tells us a lot but he admits he is not a Mopar guy and he just went through the motions, which I admire. He did have a good 10cfm over the other in the .200-.400
Without going back and looking in my flow sheets I'll just say that at one point when messing with the valve job in Bowl after doing the kind of short side work I do I was seeing very high numbers .1 through .400 but only around 240 something/barely 250 at .500 and then hanging...
For example with the stock 2.08..
@.200 147 cfm
@.300 220 cfm
Once I work that head up to the peak flow I desired which was around 282 or so that same 220 turned into 190s just like Eric's and just like the CnC had he showcases and gives his opinion on.
I would like to hear from others including Jim ,Dwayne, Jesse on this.
Which head would you rather have on the street one doing like the CNC version in the video or one flowing huge like that 220cfm .300 number?