Ariel Owners Motorcycle Club

I have several Mll square 4 heads,Question: one set has a bevel cut a along part of the flat mating block surface of all 4 combustion chambers and other sets do not have that bevel cut.Have seen pictures of the bevel cut heads also.Is this factory or modification.

Could you post a picture or two please??

Just so we can be clear about the issue.

Bob.

Have seen several other photos of these heads like mine

I suspect that someone has fitted high comp pistons at some point and this is to clear the piston. I have just done the same on my Traction Avant (its a car)