240 Where is the best place to go for custom gaskets?

So my rear tail shaft gasket on my AW 71 is leaking after a repair not even a month ago..

I'm thinking that I need to try a different type of gasket material. Perhaps rubber?

Any suggestions or notable places that can make a gasket if I send them a scan?

Thanks

did you use a torque wrench to put it together and are you sure the sealing surfaces were clean and that the gasket wasn't 180 degrees backwards?

Its two flat pieces of aluminum... how can it not seal.

I've always used a thin layer of RTV on that gasket. It helps seal them up. You do get quite a bit of oil in there since it's the area where the governor is for the trans.