ok, i'm putting an act clutch in my (for now) stock ls, and am considering a 7-9 pound flywheel as well...i was talking to a friend earlier and he said that putting an aftermarket flywheel, or anything aluminum for that matter, on your setup requires balancing the crank....i have never heard this before and was wondering whether this has any relevence to my application...i know honda cranks are pretty well balanced, but does anyone know about this?

 

some people do balance the entire short block after everything is assemblied, but as long as everything is/was balanced in the first place its not necessarily needed. Basically its good to do, but your car will run fine and have a long health life without it(as long as all the other components are balanced before they go together).