Can anyone tell me the inside diameter of the oil filler tube on crossflow/pinto/essex please?

I'm modding a V8 cover to take that style of vent cap, and wanted to get going before the cap turns up in the mail.

Cheers.

The hole is 35mm diameter with a chamfered lip of about 2mm wider each side. The cap extends down 35mm, with the O ring 10mm from the bottom. I have a pinto in the garage.

Thanks very much.

I can get one made up, welded on and off for vapour blasting.