There's a surprise round every corner when you own a classic car! Well done indeed recovering all the bits! An engine out to get the front end apart and sump off would have been immensely frustrating.
I think at the time the bucket and shim arrangement was perceived as very up-market. Normally only to be found on Astons etc. The theory is good - set up at the factory and then forget for life. But it relies on a bullet proof valve and seat design, which unfortunately was not delivered. In the UK Ford showed the way to do it on the Pinto 2ltr with adjustable rockers off the top of the cam, but that was a few years away when Rover finalised the design of their four. Even then Ford forgot to get the surface finishes right and the rockers destroyed the cam in short order and it was left to the aftermarket specialists to design a roller end for the rocker! For Rover, something like this was inevitable once they had decided on an inline run of valves. About the only alternative at the time was an off centre cam location, either in the head or as per Riley in the top of the block.
In todays world you can make a major improvement by using stellite valve seats and getting valves made up in a modern material. Then it really is fit and forget and you can use unleaded as well.
Chris
