[moorepower]

We have seen alot of both kind of headers in the shop, and I have to say a slip fit with sealer is the only way I would recomend, unless the flanges are 3/8" thick or thicker. Any flange thinner thatn this will bend eventually when tightning. If you do use them, don't overtorque and do use blue locktight on the threads. The blue will handle the heat and you will be able to get them loose when you need to. moorepower