V8 Head Gaskets - Composite Vs Tin

[Budgie]

I'm doing a full rebuild on a 3.5 EFi V8 from the Rangie and I have a set of composite gaskets for it.

Before I go fitting them, has anyone else fitted these to a 3.5 to replace the standard tin head gaskets and what (if any) power loss did you notice using the thicker composite head gaskets?  :?

I do have a set of tin head gaskets as well so I have the choice if it looks like the extra thickness will drop the power too much.

Oh, and the engine is fitted to a 4-speed auto, if it make any difference.  

[Range Rover Blues]

Have you skimmed the heads? if so the composites are a no-brainer.  Tin ones are about 0.5 mm once fitted, the composites are about 1.2 mm so you can skimm some head away.

Blue had skimmed heads and tin gaskets, the timing was set at 2 deg instead of 6 but it still burned valves like they wer going out of fasion, fitted composite gaskets and no problems since.  To give an idea I was getting 205psi at cranking before and 165 psi after.

If you are going to that much trouble I would suggest you at least get the heads checked for flatness if you don't just get them skimmed.

[Budgie]

I thought about geting them skimmed but there isn't anywhere on the island that does it so they would have to get sent to the mainland to be done, even more money and wasted time!!  :(

They have been checked for flatness and both heads are fine. I think I'll just go ahead and use the composite gaskets, if we loose a bit of compression in the process then I can also work on it later.

Thanks for the info.