I still got a couple of pieces of equipment kicking around that are still running there original flathead engines. Couple of Continentals, Hercules, and a IND 30 Chrysler. ALL of them have pressurized lube systems and save for the Chrysler have spin on oil filters. Its time for their spring time tune ups and torture test to make sure if called upon they can actively perform. I'm thinking there all getting Delo 400 30W is there any reason this is a bad choice for these monsters of days gone by?