How to do an engine assessment on my wifes 81A?

[david.skinner]

great advice. I have no idea of the miles on the engine but it is very tidy externally and doesn't smoke at all. The previous owner changed the oil last year and used Penrite HPR 30 Oil looking at the receipt. I don't have a tacho but the idle is pretty slow as I adjusted it up just a bit from stalling. It appears to run very well from my limited experience. What do I test with the Vacuum gauge btw? much appreciated.