No need to run a cheap oil through your motor, you are defeating the use of a good oil

I use the Wynns flush on my and my customers cars here, have used it for over 20 years now and swear by it. This not flushing old motors is a load of rubbish, have done it so many times and onyl had good results. I always do this, better to keep it clean now than have to try and clean it out later

The Magnatec thing seems mainly to be on the J and later motors, I assume that there may be been a different stem seal material used perhaps either way, I know of several J and L series motors with stem seal smoke and the common thing with all of them is Magnatec oil.