Anyone have to "clean up" BBK headers

If you are running stock heads (small exhaust port), smoothing out the the header inside welds will not do anything in my opinion. The 1 5/8 headers have a big enough port where the air virtually hits the tube of header and not the outsides.

If you are running aftermarket heads (bigger exhaust port), smoothing out the header inside welds won't hurt anything if you got the time to do it. It would more likely be a restriction since the the exhaust port wall on the heads and headers are closer to matching.

If you want to do it, just try to do it yourself, so you don't feel like you lost any money...that is just my opinion.

Also, the BBK collectors are 2.33"...I don't think you will see a gain increasing the collector less than 2 millimeters.