SJ was 1000 ppm ZDDP/phosphorus, but grades > 30 like 15w40 didn't have to meet that limit. That probably also applies to the 20W-50.
So, while that 20W-50 may have a good amount of ZDDP, I would be inclined to stick with the Delo 15w40. For one thing, the Havoline 20W-50 SJ is more than likely a Group I based motor oil. It won't have near the thermal/oxidative stability and overall performance that a modern Group II based oil like the Delo 15w40 will have.
You could use the Havoline, but I would keep the oil change quite short ~ 2000-2500 miles max. I think the Delo is better.