I've been doing some research to find what mods what produce the best combustion chamber design for my next race A15. I think its silly to bother porting a head if the combustion chambers are not given any consideration.

I was thinking of placing a head gasket on the head and tracing the bore onto it. My block is +2mm so there will be some meat to take off the head around both valve seats in order to let the head breath better, especially when the valve is at low lift. It will ofcoarse have oversized valves fitted though I'm not sure exactly what size I will go.

There is also some performance to be gained by removing some material around the spark plug. The idea here is to get as much fuel+air near the spark to achieve a quicker burn.

I've even heard some people pack spark plugs to align the electrode to the centre of the cylinder.

Then there is the issue of removing or rounding and protrusions to avoid hot spots in the head.

Comments anyone ??