Header/manifold dyno test

DionR said

Be aware that the cam in the motor is so small that it barely has bumps on it. So the exhaust isn’t the choke point. The test is kind of pointless and shouldn’t be used to say “headers are only worth 15 hp”, or whatever the difference is.

Put a better cam in the motor and I bet the differences will be much more significant.

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True overlap likes long tube headers , but most wanting to run manifolds are probably not trying to push it over 350hp with fairly mild cams doubt even with something like an xe268h cam the difference between manifolds wouldn't grow much if at all, what I take away from it any 360 manifold is fine no need to spend $$$$ on 340 one's, and if you already got 318 manifolds on your not losing much, probably the same with 273 one's.