2-1/2 Litre Starting Carb Flange and Gasket

Here is the gasket I scraped off the flange that bolts to the head, a kind of pink fibrous material.


Has anyone seen that sort of material before? What is it? Can I just make one out of cardboard?

There is a drain hole in this flange, which was plugged up with crud.

The pink stuff was a fairly common gasket material: I think the carb gaskets were sometimes made of it, and the water bracket gaskets on a P6 Rover are made of it. Tough as nails.

I would not use cardboard, but rather a good quality fuel-resistant gasket material. No silicone here, as it is NOT gasoline-resistant.