i have the exact same unit on mine, u should also check that the pistons can be moved if u ease off the top adjustment nut.. mine was clogged with oil/crap and jammed so im currently cleaning the whole unit
u can block off the return pipe with whateva, but i have found turbosmart does making blanking caps in the correct diameter, probably best way to go, $16 odd bucks
ps. what u doing with ur stock as i might be interested in returning mine back to stock