I do not know much about building one, but ITBs FS:SOHc ITb'S
High compression pistons, rods and bearings, crank, cams, valves, and valve springs, other shit that I dont know nothing about, and trust me a SOHC hitting 200 on the ground all motor is very possible, and very costly.

now getting a SOHC to hit 200 on the ground boosted, thats not hard at all, do it all pushing less then 12psi and tuned right.
Doesnt even take much motor rebuilds to get that.
If your gonna boost a SOHC think about getting, valve springs replaced, rods and bearings, and rings, port and polish the head, performance (aluminum head gasket) and your motor will handle 12psi as a daily driver and track car all day long, so long as you keep it tuned.