Supercharger coolant reservoir cap questions

[TexasBlownV8]

Is the GT500 supercharger reservoir (degas bottle) cap the same as a 4.6L degas bottle cap?
I have a Canton intercooler reservoir for a GT500, threaded for a screw-on cap, and a stock 4.6L cap doesn't screw on very well at all, almost like the threads a little different. Same results with a Kenne Bell reservoir cap, which fits a 4.6 bottle fine, but very tight on the GT500 reservoir.

 

[Boozshey]

I thought the canton tanks were the same... :/ strange

 

[TexasBlownV8]

Though so too. And it says 'uses stock cap'. Maybe it does, but the threads look ok and the two 4.6 caps I have sure don't fit right.

 

[Boozshey]

Threads? You have screw on type? Mine is more of a make sure the tabs fit in the groove and twist to lock... Is that what you mean?

 

[TexasBlownV8]

No, it's the screw-on cap type. And I checked it closer today: the diameter is the same on the outside of the threads, but the thread teeth are not exactly the same pattern (on the Canton)! The threads are good and clean and not damaged in any way, just doesn't fit.

I really need to know what to do here, whether I need a different cap, or what?

I'd hate to have to use the plastic Kenne Bell reservoir, but will in the interim if I need to.

 

[Boozshey]

Sorry man, can't help you. Mine is the tab style...

 

[TexasBlownV8]

No problem. I was hoping some GT500 owners would chime in with the answer.