Lynn,

Do you think that's why some PP are sloped down - i.e. to limit extending the closing event too far up the RPM band,

Something to think about.

Just when I thought I had it sorted out.

George (down under)

I don't think there was an attempt to affect any performance with that angle. It just makes boring the hole quick and easy. The factory port runners are parallel with the pan mating surface. For much of the time (in degrees) before closing the rotor surface is also parallel with the pan mating surface. It looks like a far better situation than the angled inlet. It might also add a bit of support the inner wall.

 

Use a thick walled tube with a light press fit into the inner wall of the housing. Lest you flex the chromed surface and make a crack when you torque up the stack. Torque it up empty and dry several times to be sure this did not happen.

 

 

Lynn E. Hanover