Exhaust diameter size for 408 CID
I think the usual is 1 7/8ths primarys and with either 3 inch true dual or a 4 inch Y pipe set up. I would go with the True dual for sure. I've been looking into this as well because I want to build one. It seems alot of people are getting by with the 1 3/4 primarys on the budget builds. And I think I might do that untill I got money for the 1 7/8ths since I already have headers. Also if you go to the Dyno section there is a sticky for 408 builds and there dyno numbers and set ups. Hope this helps some.
I failed to mention that the 408 stroker is going into a 69 Nova, so it WILL be running a TRUE DUAL EXHAUST system. I'm just not sure of what size primary tubes to use and how big of a pipe to put behind the headers.
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For the Nova I would do a 3" dual exhaust with X pipe. Put some bullets in it and you should be golden. Put dual cutouts in it for when you want to get rowdy...Is this a traditional SBC or LSX 408?
1 7/8 on the headers, with a 3" dual exhaust will fit your needs, unless you are going procharger or turbo, in which case, larger would be better, like 3.5.
This, from someone who switches exhaust like most switch underware.. lol
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Excessive, Go with 1-7/8" headers. I believe they'll net the best overall results. Go 3" with an X-pipe on the exhaust. I may have the headers for your combo. Let me know if you need more info. You can reach me at 631-608-1986. Thanks.
Nick
Nick
