H pipe or X pipe......

DRENO said

Another question,is 3" pipe too big for a mild smallblock? Do you need a certain amount of backpressure?8)

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Back pressure is bad for any internal combustion engine. But going to big on the pipes can actually slow down the air flow enough that it effectively increases backpressure by reducing the scavigining effect and will lower the power output.

That being said on a mild small block the only thing you will get from going from 2.5" to 3" exhuast is more noise.