Hi Bob, I always trust and respect your knowlege, as I have been following your posts for some time now. Your web page helped me get reliable runs out of my ST 2300, ended up with the Perry carb and pump. That engine is presently on a GP Giles 202, and when I crash it (not if) I will be looking to build my first 2 meter pattern plane (maybe a Typhoon 2000). The ST 90 is on a Bravo 303 pattern plane, but the stock muffler is a whopper! Tower sells a ST header for the 90 but are out of stock till January, maybe I'll wait for that and use a MACS pipe on it. Do you have any other info on making your own headers? I saw the bit about brazing sections on your web page. How about using brass? Do you think the thin wall type commonly available to hobbiests would hold up? Not sure about bending that stuff without kinks and slow cooling of brass causes brittleness (opposite of steel). Any thoughts would be appreciated. Thanks, Steve