turbo chevy small block

I have a 1973 400ci small block in a 1987 pontiac the motor has 202 valves and headers high rise intake and a HEI distributer and a comp ratio of about 9to1 and I'm in search of more horse power I've been looking at tubos and trying to fogure out what I have to do to the motor to run either a twin or a single turbo any information would be greatly apprieciated

1. fuel inject it, or spend $$$$$$$$ on a blow thru carb
2. Fab two exhaust manifolds from sch40 steel weld fittings and a flange
3. blow it up about a dozen times getting the fuel and timing right