I've had econo 810's in front of me that were rough cast on the shallow side of the chamber like a factory head.
Are yours machined looking like OP's and if so are they 1 st gen or what yr? Did op mill his stands off, cause econos have stands.
I searched that casting number online and if I am reading it right, they could have come on either open or closed chamber. So it's still possible they could have been machined open. ......IF I am reading that information correctly.
