What would be best method to match header gasket? gasket to header? gasket to ports?

[5spd GT]

Well here soon I'm getting BBK 1 5/8in. longtubes to put on my car. I have afr 165's and was wondering what is the best method to match the gaskets. Fel-1415 is what I would use.

Should I match the gasket to the header opening or to the exhaust port opening on the AFR's? What would be best and why?

Thanks!

 

[Bladez5_0]

I would match it to whichever has the smaller openning. You get the most seal and don't lose any flow.

 

[5spd GT]

Good point I'll look into it...

What is something that is good to trim a gasket like a header gasket. Razor's just don't work...