2.5” down pipes to 3” dual exhaust 81 Firebird
 

As the title indicates, I was able to get a 3” stainless dual exhaust for a great price. I have rare manifolds CNC out to 2.5” and mandrel bent down pipes. I then transitioned to the 3” x pipe and the rest of the system. Will this lose power because the pipes are different diameter? Does this do something to the exhaust pulses that may hurt performance? Thanks

I have done this, but do not have any before & after tests for comparison. My guess is that you will not notice any seat of the pants difference from having the larger mid and tail pipes.

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As long as I don’t lose performance I am ok with this setup. I have read that racers use “stepped” exhaust to tune mid range etc.