We are having a lot of flow issues with our heads stateside, especially the upper RPM powerbands; I take the approach that Ford created the CVH setup with the learnburn like that here in the states, which accounts for such whicked torque to horsepower ratios and the good gas milage, where they have seen over 40mpg here. I believe this is the key to unlock the power, and allow it to flow even more. I'm still contemplating getting some form of valve grind, though I will have it ported and port-matched.

I have an extra lean-burn head, a 1.9sefi that I think will be the guiney pig in this. Don't know which method of testing I will take, though. Seems to be a tricky machine job to finish the combustion chamber in it's orb-state, if you will.

I can understand once the true-hemisphere chamber is completed with porting work done how it can flow some serious air, just by a fluid dynamics approach (each of the four cylinders capped off at the top with a perfect (well relative) half-circular sphere, which has no rigidness to worry about on the compression stroke (maybe slight where the valves are, etc).

I'm pretty certain this is the route to take. Hopefully I will be making the power in a year or two to RWD it; thinking T56 (bolts right up to the CVH, if I recall correctly two boltholes vary..).

Checkout my cardomain, updated.