i have the felpro 1406(?) gaskets and the rksport headers. however the gaskets holes are a bit wider than the primary openings of the headers. will opening up the header ports a little to match the gaskets hurt flow velocity or anything like that? also, what is the term for the machining process where one makes somehting perfectly flat? i.e. making a flange perfectly flat, even
thanks.

 

also, for those of you with rksport/as&m headers in a 94-95 car, did you have to extend the o2 sensors?

 

I had to extend my driver's side. I just used an extender from Thunder Racing, not splicing the O2. Although I've done that before.

I found the 1406's to be restriction on the RK's, not the other way around. Kind of odd... At any rate, 1409's are supposed to be the right fit.

 

the primary holes are smaller than the 1406 gasket holes. should the primary holes be larger?? do i have a wrong part?

 

anybody else, i would like to install these suckers soon.
thank you.