Ford Falcon XD 1979
5.8ltr Cleveland C4 Auto

Pacemaker Headers PH4070
Twin 2 1/2" X System
2 1/4" Tailpipes

Having owned this car for eight years i have tried every different type of exhaust system combination

Just before the left hand muffler i installed a vacuum operated valve, this enables me to close off this side of the exhaust. When closed the the exhaust gas diverts to the right hand side an runs a single system, this increases low end torque and also reduces the noise level by 4db @ 3300 rpm
The valve is actuated by inlet manifold vacuum, ] i can apply vacuum to the valve so it can be kept open or closed to suit.
Because the valve uses manifold vacuum, when switched to the closed position the valve will automatically open when i put the foot down [lack of vacuum] then re-closes

Please Note
Must pass epa noise test with
exhaust valve open

As the collectors pass under the gearbox
cross member the headers sometimes touch
the outer edges of the cross member, when
this problem arises [very occasionally]
we modify the cross member
Click here for details