I bought a phenolic spacer off ebay to try and help reduce the heat transfer from the head to the intake manifold. I've read somewhere that the surface of the phenolic spacer acts somewhat as a gasket......thoughts?

 

You'll need 2 OEM intake mani. gaskets, one on each side for proper seal. You also need some longer studs.

 

...I'm thinking the same.

 

For that style of phenolic material you still need gaskets.

 

Any idea how much power (if any) these things net?