[chicagobears2010]

I was wondering if anyone replaced their exhaust manifolds on the GT. 2007 Gt is what I have, and it currently has 150k miles an throwing codes for both cats p0421 & p0431 Warm Up Catalyst Efficiency Below Threshold. I plan to replace them i'm just unsure which brand I should get after reading some of the reviews, some people said they had to make modifications, an others say didn't seal properly. Has anyone replaced these an had no problems fitment wise, and if so which brand did you use an where did you purchase them?

 

[Sabertooth^2]

Road Race Engineering is the go to, and I've got them on one of my GT. They're in semi-production, the rest like OBX and RIPP are loooooong discontinued and hard to find

 

[InheritedGT]

Road Race Engineering is the go to, and I've got them on one of my GT. They're in semi-production, the rest like OBX and RIPP are loooooong discontinued and hard to find

After getting the tune, I looove the sound. I’d love to get my hands on some RRE headers...But in that vane, what about punching out the stock ones? Not worth the effort compared to the price and gains of the RRE headers?

 

[pcfreak4]

After getting the tune, I looove the sound. I’d love to get my hands on some RRE headers...But in that vane, what about punching out the stock ones? Not worth the effort compared to the price and gains of the RRE headers?

I don’t believe you can punch out the Gt ones too easy because of their design and angles unlike the Gs

 

[Sabertooth^2]

GT ones definitely can be knocked out. It's a bad thing to do though

What you'll end up with is 1 head running hotter than the other though, and in effect have no exhaust manifold runners on one. It would put you into the exhaust flow territory of a low model tractor in the 1910s (actually). I don't know of any production car that has used a worse design than a gutted GT cat would be. It would be prone to knock on long/hard drives, and make terrible power