This maybe another alternative to diesel oils for early break in,
Penrite Australia make an SAE 20/50 dedicated mineral based running in
oil,
API SF/CC rated, this
oil is recommended for 500miles only and has no friction modifiers, and low levels of detergent. Plus has high levels of
zinc 0.136, phosphorus 0.124.
The running in
oil may not be that suitable for a race type engine, and its reasonably thick but that could be so it covers a wide range of engines!