Factory manifold question

[Big Boost]

Looking at the factory manifolds, they appear to have a anti-reversion design. In the quest to achieve more HP/TQ, wouldn't the anti-reversion hamper flow and /or velocity? Has anyone ported the inlet of the manifold to remove the anti-reversion area and achieved any gains that you can report on a dyno?

[S4_NE]

Vast might be able to help, I belive they mod them and resell them

[Big Boost]

Thanks. I was aware of their port work, but was curious as to what exactly are they porting? Besides the anti-reversion area, was is actually left to port? There isn't much material around the turbo outlet area to port, and it's probably best to stay away from the EGT threaded area so I'm trying to find out if it's really worth a shot.

[S4_NE]

MTM sell a cast performace manifolds that is a option for you instead of getting the tubeular ones for the exhaust as well, knowing MTM it is big $ but there stuff is quality