When I put the 283 back in my 2 ton I filled it with Valvoline 5w-30 full synthetic 'cause that's what I had on hand. I did not do any machine work on the engine, just a cam, lifters, gears and chain that I took out of a 350 from a prior build. I cleaned the oil pump screen, new front seal, pan gasket, intake gasket, left the original rope seal in the rear main. No leaks and it runs great with no smoke. I also was concerned about running synthetic in it but I have no worries now.
