Oil Weight for the FE

[REDSC400]

At a recent car show, a few of us were talking about oil weight choice for our engines here in the northeast and how the variable seasonal weather posed a problem for us. Essentially we have to run two different oils, one a summer oil which is usually heavier and a winter oil that stays lighter in the cold temperatures.

That said, it dawned upon me that I am not well informed on the historical factory reccomendation (FORD) for the 428 Police Interceptor FE engine. Does anyone know what oil weight grade was reccomended for summer and winter use by Ford back in the day (1966?)

I did a few searches on the web but came up dry.

[SCOBRAC]

30 wt

The summer / winter oil delimma was resolved many years ago by using multi-weight oil. 5w 30 or 10w 40 for most cars year round is fine.

For a car stored inside 20w 50 would be fine year round particularly in a synthetic.