All my motorcycles are pre 1942 and my cars are from 1923 to 1972, plus the Tranny and the family X3, normally use straight 40 oil in the oldies, I am sure the rings have a gap after a very short while, a thou off the circumference equates to a decent gap, no idea how to work that out but someone will!
i ran it on cheapo oil for 500 and gave it some stick , not abuse but full use of the revs , plenty of overrun etc , sadly theres been other issues with the car so it hasnt really been in proper use like id have preferred
i spent enough money trying to do a decent refresh , i read up on it all and did the right stuff
its just had big end shells , didnt really need them but id ordered them anyway
i guess its down to being a diy shed job and break in cant have been good enough