Originally Posted by 78buckshot
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.

Believe rope seals fair better against synthetics than neoprene seals on the rear mains, no empirical data just my own thinking.

1953 Chevrolet 3100
261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY Gallery
Video of the 261 running

1964 GMC 1000
305 Big Block V6, sm420, the next cab off restoration