well i looked into what the check valve does in the BB line. All it does is keep vaccum when your car stalls. The guy i bought it from had the check valve really close to the booster itself, so i dont think it worked right every, cuz i had no braking power all the times it stalled. So i might leave it out. Now my BOV is setup right, it get good vac cuz it does vent to atmosphere, but i just get the gobble before it. With stronger hoses going to the booster, and the BOV i will see if that makes a difference.