Exhaust Question

[69Time1]

I have a 350 in my 69 GMC (after market motor 74') On my exhaust manifold (driver side) there is a lever. Does anyone know what the lever is called and what it is for? It appears to adjust the exhaust flow..

[70-Chevy]

A lever? Im not familiar with exhaust manifolds too much as I've always had full length headers. Do you have a photo by chance? Im curious to see if this "lever" is at the front of the manifold by the #1 cylinder. I've seen some guys use newer model manifolds and cut and smash the end of the O2 sensor instead of removing it and plugging the hole. Its alwasy looked like a lever to me when I've seen them do that.

Im sure someone on here will be able to help you out.

[kwmech]

The "lever" manifold should be on the right hand side of the engine. It is a 'thermostat' so to speak, it closes when cold allowing exhaust to back flow a little up through the intake manifold to help with heating up the carb to help reduce emissions. More often called a heat riser valve

[fastwillie 696969]

heat riser ==ex wife both have been removed

[69Time1]

Thanks ya'll.