The following HS4 1 1/2" SU spacer is 7.5mm thick. It has a vacuum take-off which can be sealed or used for various applications/devices.
Don't quote me, but apparently the twin carb application has slightly wider studs, thus the elongation.
To look for items in my shop, it is easiest to look in the yellow box to your lower left of "categories". Select the category of interest and all items in that category will appear. It is much easier than keywords.
For example "BRAKE" or "TRAFFICATOR whole" or "LIGHTS" or "AXLES" or "COOLING" etc etc