Classic/Antique Car Repair: engine oil, mid gauge, road speed

Question
I recently purchased a 1949 ford f-1, the engine has 4000 mi. since rebuild. What do you think as far as oil weight.
I am in Arizona and rarely does it get below 40 degrees.
thanks.

Answer
If it was mine I would be using a 10W-30 and watch the oil pressure. If it runs mid gauge at road speed you are golden. If the engine is set up with loose clearances then the hot running pressure will be lower that mid gauge and adding heavier oil is just a cover up.
Brad