Manifold marking Aluminum LS-6

[John W.]

C3 question. Have a GM manifold 3963569( LS-6)and next to the part # is GM1. There is no foundry markings on the top or date code on the bottom and no cylinder # as in the later years. No other numbers or letters appear anywhere. Any info would help.

[Joe L.]

Re: Manifold marking Aluminum LS-6

John-----

There should be a Winters Foundry "snowflake" somewhere on the top of the manifold. It's possible, though, that someone has previously ground it off. The "GM1" indicates a pattern number.

The lack of cylinder numbers indicates a 1970 manifold. So, it never originally resided on a Corvette. However, the manifold was used for 1970 Chevelle LS-6 and L-78 as well as 1970 Camaro L-78. The 1971 version of the manifold had the cylinder numbers. In PRODUCTION, these were used for Corvette only.

Date coding for these manifolds is usually under the steel oil shield. So, if the oil shield is on the manifold, you won't be able to see it