VALVE COVERS HAVE A RUBBER GROMMET THAT HAS A TYPE OF BAFFLE IN IT.DISTRIBUTOR IS A MSD 85551 PRO BILLET TYPE RIGHT NOW I HAVE THE SMALLEST STOP(BLACK)BUSHING IN IT AND THE WEAKEST SPRING'S.JETS ARE 75 FRONT AND 80 IN BACK.I THINK IM GOING TO GO TO 72 FRONT AND 78 REAR AND SEE WHAT HAPPENS.