Where to buy a large AST coolant cap?

[mo_yassin]

I recently bought an FD, and it already came with an aftermarket metal AST. However when I changed the coolant I noticed the quaity of the cap was really poor, and I want to replace it. The cap is almost twice a big as a standard radiator cap, and I can\'t find anywhere that sells them. Any ideas?
 
Cheers.

[hairyhoover]

Good question, I have the same issue!

[Initial-D]

Ask WGT as they use the large caps on their ASTs.

[m1tch]

Would it not be easier to just remove the AST?