I always just assumed that the bigger the diameter the better... Do the stepped headers really make more power?
2013 Camaro ZL1 #1440 Black M6, Roto Fab CAI, Kooks LT, 9.55 Lower pulley, ID 850's, MSD BAP, Dual Pass HX
JRE Cam Package 652RWHP 613RWTQ
2011 Triumph Speed Triple, Muffler delete, tune
1982 Honda CB900F Cafe In Progress