Just broke in freshly rebuilt 350 for my 55 Chevy. Drained off Brad Penn break in oil and refilled with Pennzoil Dino 10W-30 for 500 mile break-in. Looking for best oil once 500 miles are up. Flat tappet cam, so want to feed it a zinc-enriched oil and noticed Mobil 1 10W-30 High Mileage has high levels of Zinc...any thoughts on protection level of running it vice a good Dino oil with an additive like ZDDPlus?