Combat Commando - lowering compression

Don't try the thicker aluminium head gasket. It's so soft that it squishes out. The one I tried ended up rubbing the pushrods as it oozed into the pushrod tunnels. I then used a steel compression plate at the barrel crankcase joint which was ok. On reflection I'm not convinced it made that much difference to anything. I didn't adjust the length of the pushrods as I don't think the factory shortened them for the Combat engines. 

My Combat head self destructed so I now have a non skimmed head on my Commando and nothing at the base of the barrel.