Just thought I'd get a little discussion going. Anybody ever thought about swapping a SVT Focus header as a upgrade for the stock header? They are a common swap for Foci and the SVTF header is said to be one of the best factory or aftermarket headers yet made. I've seen a dynochart posted of a stock Focus with just an SVT header and it gained 15hp with just that mod. Our heads have the same bolt patterns, you'd just have to use the Focus exhaust gasket.
There are several problems though, with this swap and even more with swapping it to our engines. First the oil pan on the Focus is different than ours, the hump is in a different spot, but the Focus oil pan will directly bolt on to our engines. My dad bought one and is using it and my blown engine as a template for his turbo setup on his Focus.
Then you'd have to custom install it to hook up to the stock flex pipe and exhaust. You'd probably have to buy a SVT CAT and use that to help hook it up easier. It'd be a somewhat involved install. Also on Foci, it's been found to melt one of the power steering lines cause it's closer to the header on regular Foci than SVTF's. Don't know how our lines relate to the Focus. And finally the very bottom part of the header sits quite a ways from the engine and may interfere with the motor mount or radiator fans. Also if you have EGR you'd have to make that fit or remove it. You may also have to move the dip stick a bit.
It's not exactly a direct bolt-in as I origionally thought but it's been show to be one of the best headers for the Zetec. It was designed by Cosworth, and TurboTom said it was one of the best factory or aftermarket headers he's ever seen. Here's a pic from a web site that sells a conversion kit to make the SVTF header fit a stock Focus.
And one last thing. I was reading past posts on the drivability on 3" exhaust on NA Zetecs. TurboTom did a test fit of a 3" catback on a SVT Focus and found that it gained HP virtually across the entire RPM range with no losses down low. He was surprised, but said it was partially because of how good the stock header is. So theoretically, if you have a NA Zetec doing 150whp, with a SVTF header...a 3" cat back would be a good idea.
