Picture of 340/360 head porting....Mistakes?

yellow rose said

I agree 100%. But we both know that is a massive bunch of work. And we both know grinding sucks, and grinding cast iron double sucks.

If you want the power, you need to do the work.

Click to expand...

Oh, for sure it’s way more work than I’d take on.

But it looks like that’s a “test head”, so it’s not so bad only doing one port to test the theories.

With “normal” porting...... no holes, no sleeves, no extraordinairy measures........ an X head can get into the 270’s @.550 and not have the numbers get too terrible at the top end of the flow curve.
They do seem to be pretty fussy about the shape of the valve in the .400-.550 lift area....... but once they fall over, the shape of the valve hardly makes any difference.

I’m more conservative at the short turn on the 915 and later heads....... as I prefer not finding water there.