i'm having trouble trying to get headers to fit on my f250, so I've decided to just use the stock manifolds. (it's an '85, 351w 4x4)

problem is on the left (driver's side) manifold, it has a weird looking valve the bolts between the manifold and the exhaust. my guess it is for the AIR / pollution pump that the previous owner got rid of.

is there any way I can get an exhaust to bolt up onto the manifold itself (it is just flat, doesn't have the donut ring like the right manifold does), is there another manifold i can use (different truck/car), or do i have to use that exhaust valve thingie?

thanks in advance

 

That thing on the exhaust is the heat riser valve. It should have a vacuum servo on it. A temp switch mounted in the coolant, puts vacuum on the servo when the engine is cold. This blocks the exhaust and forces it to run underneath the carb through the intake manifold to make it drive better in cold weather. When the coolant gets to about 100 degrees, the temp switch cuts the vacuum off, and the exhaust valve opens. As long as the valve is in the open position, you can put it on without hooking it up. This will also guarentee if you have the correct truck manifolds, that you can go to the store and buy a y-pipe that will fit correctly.