I not sure if this is the appropriate place for this query, but it's worth a shot.

I'm running an SLP header on my passengers side of my custom built turbo, but the surface is apparently not perfectly flat. I'm running copper gaskets and it still won't seal on #8. It'll always blow out after a few hundred miles.

So, knowing that these are individual flanges for port #8, #6/#4, and #2... how do I plane these so they are perfectly flat with one another?

Jesse

 

I guess you could take them somewhere that could mill them, Or someone with a giant disk or belt sander.

 

I don't know if it'd work with the separate flanges though. I was thinking a machine shop could use the same tool that planes head surfaces, but it might be more difficult. They are definitely going to have issues holding the header for starters. Also, I can see the cutting head snagging the edge of the flange and bending the whole unit.