66 L72 427/425 858 Head Cavities

[Peter M.]

1966 L72 427/425 858 Heads have a cavity in the center near the 069 intake crossover for exhaust heat to the carb. What is the purpose of the cavaties and are they partially or fully covered by the intake manifold gasket from the factory ?

Thanks

[William C.]

Re: 66 L72 427/425 858 Head Cavities

I beleive the cavities are there to maintain a more consistant section thickness in areas of the head to prevent distortion during cooldown. The cavities are covered by the manifold and gasket.

[Stephen L.]

Re: 66 L72 427/425 858 Head Cavities

The cavities are covered by the gasket but NOT the manifold itself. If the gasket is cut to follow the exact outline of the manifold, as some believe to be the original design, then these cavities are exposed...

[William C.]

Re: 66 L72 427/425 858 Head Cavities

That is correct, the manifold and gasket are designed together to cover these. The gasket does not look as the smallblock in following the contour.

[Peter M.]

Thanks Guys *NM*