Hello Dave, i have deep enough K&Ns for the 1 1/2" stacks but right now i'm running 1/2" stubs.. .. .. is there really a difference?.. should i put the taller stacks back in?... (i own both sizes) -- Best regards, Bill L. mailto:pythias at pacifier.com '66 Sprite MKIII HAN8L49403 "the red thing" * "I'd better repeat that SOS message," said Tom remorsefully.