I've heard that the gaskets on LS1's are reuseable. Is this true.
Im rebuilding my motor right now, do I need new gaskets. I know that the head and exhaust manifolds are not reusable.

Thanks

 

The exhaust manifolds are re-useable, as are the bolts.

I would replace the front/rear cover gaskets, front/rear seals, oil pan gasket, head gaskets, water pump gaskets, and valley cover gasket.

After you put the oil pan gasket (might be re-useable?) and snug it down. Spread some RTV on the front/lips where the front/rear cover seat down onto. Check LS1howto.com's camswap guide for more info on this.

You'll probably get more (and better) answers in the internal section, so I'll move it there.