High levels of ZDDP are not needed in the GT because it has overhead roller cams. If you have a classic solid lifter type of engine, then consider the VR-1 or similar products.
In addition, ZDDP EP additives are being phased out for moly EP additives that work as well or better--even in old hotrod V8's. Technology has moved forward.
Since you're fairly new here, I'll condense everything I have read and tested through oil analysis of the oil in my GT and other vehicles. Continuing oil analysis in my FGT with almost 90,000 miles shows that the recommended Motorcraft 5W-50 oil meets requirements for at least 10,000 miles in normal use with occasional track days. So I continue to use it because I don't want to go through the trouble and expense of changing to a different oil and building up my data records with more test results. And I now use 10,000 miles as my target change interval, although I've gone past that several times with no change in oil analysis results.
Be very skeptical of any claims that one oil is better than another IN YOUR ENGINE. To anyone who claims otherwise, demand to see their data. (spoiler alert--they don't have it)
Therefore, either use the recommended 5W-50 Motorcraft oil and run it for 10,000 miles (time does not matter), because I have the data to support that recommendation; or try different oils and do your own oil analysis. If you decide to change, then do analysis at 5,000 miles. If it's still good, continue to 10,000 miles, then test again. If it's still good, you can continue to 15,000 and test again. Personally, I'm fully comfortable going to 10,000+ miles, but not 15,000, even if the test results are still good. But that's just based on my habit patterns and comfort after 50 years of owning cars. But hey, it's your car, your choice.
I mentioned time: Blackstone Labs (who I use for oil analysis) has tested old oils and oils sitting in crankcases for long periods of time. Their testing shows that oil does not breakdown or go bad from simply sitting on the shelf or in the crankcase. You can go to their website and read their latest newsletter, which revisits this question and confirms what they have found previously. They also posted a test result for a GM turbodiesel engine approaching 90,000 miles ON THE SAME OIL CHANGE. You can read about it there too.
Oil is extremely stable stuff, as you would expect of something that has to operate continuously at temps from 200-250 degrees in the mechanically and chemically harsh innards of an engine. Sitting around at room temperature for years doesn't touch it.