Just an old observation, but unless you guys are punishing your engines or driving them a lot of miles I personally would stay away from 20-50 especially if you do a lot of stop and go or in-town driving. An engine needs to properly warm up and then run long enough for it to be of any use. A lighter weight oil is also better for fuel milage. These engines were built with single weight oil in mind when new. The heaviest I use is 10-40 diesel for the mechanical lifters and 1/2 bottle of EOS with every change. Good luck
