So i took apart my first 13b. It is the cosmo 13b-re engine btw. Inside the exhaust port is this metal flange. Is this some sort of exhaust diffuser made for the cosmo? The reason I ask is that I am goingt omild streetport the engine and I wanna know if this needs to be taken out and put back in or do i cut it out while porting? or... please helpm rebuild coming soon as I know.

here's the pic:

 

Thread released so rebuilders can weigh in with the facts.....and at 104 posts, ya really oughtta be posting in the real tech boards.

Mario III