Exhaust on a 408w?

[Sites]

I just finished building a fairly healthy 408w and just got it running the other day. I'm running a pair of 4-1, longtube headers that merge into 3" collectors. The cam is made to make a "wall" of power early on, though 6800RPM, and I'm running a 2800RPM stall torque converter.

My question is, do you think dual 3" exhaust is too much? Or should I step it down to 2.75 or 2.5" dual exhaust? I think I'm just going to run two Borla XR-1 race mufflers, no cats, dumping right after the cab.

I just want to make sure I don't kill the bottom end by running loo large large of diameter tubing. At the same time, I dont want to choke the motor either.

Thoughts?

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[amr126]

Here's some general guidelines from flowmaster-

http://www.flowmastermufflers.com/faq.html

[Ziggy]

I used to own an exhaust shop and played around a lot with exhaust.
We had a 434 chevy with 832 HP.With a 4'' exhaust it only made 789.With 3 1/2" it made the 832.We came to the conclusion that up to 400 hp 2 1/2 duals was enough,400-650 3 inch duals was enough and 650 to 850 3 1/2 was enough.


There are a lot of factors that come into play with exhaust so these were rough outlines .

[Sites]

Thanks for the replys. I ended up going with dual 3" with a crossover section. The motor is expected to have a little north of 500hp/500tq, so I figured 3" would be sufficent. We're going to fab everything up today and hopefully take it for a test run later this afternoon.