Exhaust Manifold Casting #

[Doug C.]

Last fall I removed a right hand ram's horn exhaust manifold from my 66. It has a casting # of 336711 and is tapped for A.I.R. ports. My "By the Numbers" book only goes to 1969 and does not show this number. Anyone out there know the application for this casting #? Thanks - Doug

[Joe L.]

Re: Exhaust Manifold Casting #

Doug-----

The GM #336711 manifold was used on some mid-70s Chevrolet cars and trucks. It was never originally used on a Corvette, though. I don't know why that it wasn't used on Corvettes; it could have been as it would have been functionally equivalent to the GM #3932481. For quite some time, both manifolds were being produced and used in PRODUCTION and SERVICE.

The GM #336711 was also a SERVICE manifold for Corvettes beginning about 1973 and continuing until it was discontinued and replaced by the GM #372243. It would have been a correct SERVICE manifold for your application, althopugh if you have a non-K-19 car, the AIR holes would have to be plugged. In SERVICE, GM often supplied AIR-fitted manifolds as SERVICE replacements for non-AIR applications.

In PRODUCTION, GM NEVER used an AIR manifold with plugs for a non-AIR application. However, in SERVICE, especially later SERVICE, things are often different.

[Doug C.]

Thanks Joe *NM*