In October of 2008 I decided to tear down my engine to replace the worn valve guides that I didn't replace when I originally built up this engine.  While it was down, we found some issues from running the high compression (8.7:1 vs 7.0:1) C-85 pistons that caused me to decide to downgrade the engine back to a stock O-200.  With the plane being down for a several weeks, I decided this would be a good opportunity to build the new exhaust I've been promising myself for several years.  Additionally, with the lower compression pistons, I hope to regain some of the lost horsepower by building a much better breathing exhaust system.  

All of the papers I have read say that the small Continentals don't have enough valve overlap in the cam to take advantage of the scavenging of a crossover exhaust system.  Consequently, I decided to make life a bit easier for myself by welding up 4 separate headers using 1 1/2" mild steel pipes from the local muffler shop.  Yeah, I know they are heavy, but I can weld them with my torch and custom build the whole unit in my hangar.  I visited a low budget muffler shop and had them bend up two 7' sticks of  1 1/2" tubing with a total of 8 - 90 degree bends and 4 - 45 degree bends.  I bought a set of mild steel flanges from Aircraft Spruce, then simply cut the pieces of pipe and welded them back together to build my custom exhaust.  Total cost , $100.