Hey all, when I tore my truck apart I noticed that the factory 5.3L exhaust gaskets were possibly a tad bit too small. Part of the gasket circumference has carbon soot in areas that indicate the gasket is protruding into the port area. I would like to use LS3 gaskets part # 12617944 which I have laying around. These are slightly larger than the ports on the manifolds. Anyone see an issue with this? Normally I would not think twice about using them on an n/a build but on a turbo setup I thought I would make sure. The heads being used are unported 862 castings.

 

I would just use them. I doubt it will be any difference on a stockish motor.

 

I wouldn't see a problem using them as long as they have decent contact area with the flange. Ever thought about port matching the heads and manifolds to accommodate the bigger ls3 ports?