Help with exhaust opinion!
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NOTHING LOL, maybe stroker kit and stage 2 cams with long tubes and flowmasters
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There's two things to note though: 1) the power adders on the one chart move peak performance to the right by about 1000 rpm; and 2) the charts START at different rpms. Without the other power adders, I'd guess the short-tube header gains would be smaller but it can't be proved one way or another with these charts. I'd bet though that unless you have these other power adders, you won't see these gains with shorties; that's probably why JBA did the dyno run the way they did.
Also note that with the shorties on the very left hand side of the chart (at a HIGHER rpm than the long tube chart) that it the advantage won't kick in until you get to a higher rpm, looks like about 2000. Again, you can't prove it with this data, but I'd bet that without the other power adders the benefit of shorties wouldn't kick in until an even higher rpm, maybe 2500 or even higher. This is consistent with the known characteristic of shorties that because they're not at the optimal tuned length (~48" or so, depends on tube diameter and desired optimal rpm) that their benefit at lower rpm is substantially less; they have to overcome a lot of ineffieciency before they do any good.
Link to tube lenght calculator
The plus side of shorties is that they're less expensive, easier to install and create less interference.
Another thing to think about is heat. Adding heat to the engine compartment is a power drain. Ceramic header coating acts as an insulator and causes more heat to be pushed out the exhaust pipe before it can leak into the engine compartment. Header wrap does the same thing. Use them together for even better results!
Brad