While I was away on the Targa rally , I bought a set of fenton headers and twin carb intake. I thought I got a real score.
I am home now and inspected the parts properly.
The fentons are very poor quality control.
Exhaust outlet on one side is 53mm and on the other 45mm !
Intake has very big step in the gas flow area that WILL impede performance . I think this has just been made for looks.

I have some engineering work to do now to make these parts good.