[99 Civic Si]Necessary mods for DC JDM 4-1 header on b20b block and b16 head

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Apr 22, 2021 | 02:51 PM

Bruh

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[99 Civic Si]Necessary mods for DC JDM 4-1 header on b20b block and b16 head

So from what I could find, it seems that the DC JDM 4-1 header is the way to go for an aftermarket header, but the listings that I've seen say that the JDM one is a little bit longer than the USDM version. How much of/would this be an issue?

Apr 22, 2021 | 05:20 PM

tony_2018

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From: Still hunting that foo up there

Re: [99 Civic Si]Necessary mods for DC JDM 4-1 header on b20b block and b16 head

DC headers made different headers for the USDM and JDM market? Didn't know that.

Apr 23, 2021 | 07:13 AM

spAdam

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From: Boat on a Hill, CA

Re: [99 Civic Si]Necessary mods for DC JDM 4-1 header on b20b block and b16 head

Yes, they had one that fits in place of a 98spec ITR header. OP, you’ll need to shorten up your cat (or test pipe) by about 1.5” and replace the flange with a 2.5” version to make this work.