[AT] Detergent oil opinion

[Dave Ernst]

I know we've beat this discussion about detergent vs non-detergent oils in 
old engines and tractors to death but I'm interested in knowing the best 
ideas about this issue in my current circumstance.
I am currently completely rebuilding a 1939 John Deere model H tractor. The 
crankcase is absolutely devoid of any foreign matter.  But what I have is 
1939 vintage metals in the head and cylinder, babbit bearings and modern 
metals in valves, guides, pistons and rings. The reason I state this is once 
I rebuilt a Cat 50 diesel, used modern rings in original cylinders, filled 
it with Delo oil and the rings never did seat.(but Bon-Ami forced the 
issue).
Will detergent oil suffice for this old girl?

Thanks in advance,
Dave