haha, Mazda

Yes, in general hi-swirl is best for mid-range but not for high-rpm power. Remember how the original Chrysler hemi had awesome power but poor part-throttle response. The new hemi is high-swirl.

* The newest A12 head (G61) has combustion chamber like the H95 but with regular round ports.

* The previous H99 A14/A15 round port had a hi-swirl chamber design instead of hi-swirl port design.

All three are good mid-range heads. For people that prefer not to "rev to 6,000 rpm"

G61

I do have the G61 for this reason but its not the same chambers yet closer for sure to the less swirl practice of today hipo 2v chambers in race heads and aftermarket upgrade chevy and harleys. Will need serious steady hand weldling & blending skill few have to pull it off.








https://racemagazine.com.au/tecset/wp- ... ploads/2015/02/Head29.jpg