also, to get REAL power from a SOHC engine, you lose a lot of driveability. you can make STUPID power with a B18c while retaining stock cams, etc. you don't have to open the engine unless you want so much you need pistons and rings.
the car can have 500whp and still get 30mpg and idle like stock. you can't do that with a SOHC. single cam engines have to be built as crazy as possible. it's very expensive, a lot of work, and at the end you end up getting beat by B-series cars.
but.. if it's all about seeing what you can do, and not being faster than everyone? i say do it. cars are an expensive hobby either way, but it's the most fun some of us can have. go crazy, man. see what you can squeeze out of that lil engine!