you want to know what is different? as far as i can tell it is cast much thinner than my c7-k head.i sonic checked the deck and its much thinner and has not been milled as much. the ports are either cast better or someone ported them. the knot that is just on the top of the exhaust valve is gone. the short turn on the intake is rounded then my c7.what i wanted to know is : any ideas on the head and why were sk heads made? if you want any info email me directly.