Oil to use for break-in

[drabik@solaris.gatech.edu (Timothy J. Drabik)]

I can't remember who requested this, but I promised it:

I used Valvoline Straight 30-weight **NON-DETERGENT** oil for
break-in, as recommended by one of the shops that did some machine
work for me when I rebuilt my Spit. engine.  The oil specifically
says "not suitable for modern engines" on the label,, so I
suppose this means it should only stay in the engine during
break-in.