We're going back nearly 20+ years to when I was a service mechanic...
I believe it was the 10/40 Magnatec but my memory is a bit vague
For better oil consumption, check the valve guides and stem seals are in good condition on a CVH
They tended to wear faster than most
Valve stem seals are easy to change without taking the head off
I've always rated Morris oils
I did extensive testing with them when I was running a mixed breed bunch of historic racers in the HSCC
Their 10w60 competition oil works incredibly well
We even ran it in both the Roadster and the Aero in both Britcar 24 HR races
Mind you, the Aero damaged its air filter and ingested a fair amount of dust and snot, which didn't do the rings any good
I think by the end of the race we were tipping in Tescos cheap as chips multi grade ....
Simon @ Sifab.co.uk