1 5/8 headers Vs 1 1/2 on a 3.0

[matty74]

Will a 1/5/8 header give you better performance that a 1.5 header like ssi?

hypothetical.

RSR spec motor with webers would the former allow for better performace vs the ssi?

[chris_seven]

We have a 3.0 litre Twin Plug motor running 10.5:1, 1.625" headers with GE60 cams, PMO 46IDAs which produces about 280 bhp with a very flat torque curve from 2750rpm.

Never tried smaller headers or SSIs