Melling Timing Kit 5.4 3V vs fear of non-OEM parts

The guys in South Florida use 10W-40 synthetic oil. The higher viscosity is not a problem because there are no freezing cold starts here. I've been using 10W-30 syn in mine with good results. 5K changes, 160K so far, no probs and don't expect any.
I dumped whatever it came from the selling dealership with after 900 miles and put in 10w30 full syn. It starts fine in the single digits F with that, no unusual noises, we had a very atypical week for Central Texas back in February.

Changed again in April with a mix of 4 quarts 10w40 and 3 quarts 5w20.