fift9er: The OD of the spacer is 1.725", .440" high. The valve sits inside, 1.5" ID, from the bottom of the inside to the the side that fits on the head is .300" There is also a tapper on the bottom outside. These are much more than a shim or washer and probably worth the $49 that SC asks for them. SC part #6078. All are as near as I could mic. Installed hight maybe 1.68".
most likely not worth the hassel to make cheaper to just buy them .