How does HMF slip on fit stock header AND powerbomb?

[kilabeez0]

Does the powerbomb header have smaller diameter where it meets the silencer like the stock header?

[Hotdog]

HMF slip on will fit the stock header and a Powerbomb.

[cals400ex]

the power bomb should have very very similar dimensions as the stock header. this aftermarket header is made to be used with slip on silencers.