I have recently been told, but have not seen, that RSR heads were modified with an 'oil gallery' to lubricate the exhaust valve guide but I must say I find it difficult to believe,
I am told that there is a 'pocket' machined as marked in red machined and then a fine drilling is made into and through the guide.
If this is true there must also be mods to the cam cariers?
Anyone seen anything like this?