Huh?? Blanket KIA statements should be avoided! I've got two sets of Hooker SuperComps here, 1-7/8" primaries & 3.5" collectors. They are early 80s vintage & when u hold up a Percey's or any other good copper gasket up to tye dogleg flange, the flanges ports miss by a good 1/4' all around the widest part of the ports. These were almost $300 in 1980 & over 5 now. Summit customer service wouldn't answer my question / request that they hold up a gasket (Percey, NOT Hooker) to them & see, no way I'm putting Hookers on anything EVER again. Eddie had the same notion as me, good reviews heard about Headers by Ed. I read somewhere a few yrs back that he is THE man to see for high HP tri-y headers, so he can have my $750. I believe that Jeff Lee uses Ed's. I bet your original question was about jeep.headers...sry. I refuse any discussion of choking down 550HP & 7500RPM capable heads for trailriding....Putting 500HP in a trail rig to dust off Detroit tinfoil with 45yr-used Wisconsin iron & forged steel is a worthy endeavour ...LOL