I wouldn't say the flat head twin is junk by any means. I ran one competitively for years. If you are going to run an opposed the better of the engines is the 46 cube with the pressure lube system. We ran one for 4 years with 0 mechanical problems. The only thing I have found is that after a race when you shut the engine off the coil would heat up from not having any air circulating around it. This would cause the coil to stop working, we solved this by placing a fan on the flywheel after we shut it down. to keep air circulating until the engine cooled off.