I am new to this forum. Actually I am new to the whole K5 mania. I recently got a 1980 Silverado K5 with rough country four inch lift with 36 interco super swamppers. My question pertains to breaks, in particular the break booster. My truck is very slow to come to a stop and it emits this swoosh sound while I press the break pedal. I think that I may need a new or more powerful break booster. I just don't know which one of the "JB's" (jb5,jb6, etc) is correct or better. does any one have any ideas? thank you.