I just replaced the stock slip-ons with a set of Rinehart's slotted slip-ons that sound and look great. I was surprised how restrictive the stockers are . My question is why do the factory headers reduce so much at the ends?.

is it to increase back pressure?, or?....

Thanks...Scott

 

Stock Mufflers have the catalytic converters in them, the head pipes are open to the mufflers.

 

I know the cats are in the mufflers, just saying how completely restrictive they are. The very ends of the headers are open BUT reduced and use a graphite-type exhaust gasket around the header to go inside the slip-ons.....I was just wondering out loud what the real reason for this reduction was other than creating some back pressure.

Thanks...Scott