NAPA Gold filters are made by Wix. The "5" in front of the part number is NAPA's add on. For example, a 51348 NAPA is a 1348 Wix. I've also used Hastings in the past with good luck. AC Delco, well I work in a GM dealership and I use them on my daily drivers with no problems. GM has to make sure they are of a certain quality. Remember they have warranties in effect so they will not cut a lot of corners as engine damage would come back to bite them quickly. What I do not agree with is GM changing the PF35 which was the long (actually there was one, a PF932 that was longer, held about two quarts) version of the PF25, Chevrolet filter to the PF1218 about a inch shorter than the PF35 and the PF454, a even shorter filter than the PF25.
In my view, the more filter media, the better.
Oils are a real mess due to reductions in Zinc levels. Used to be that Diesel oil had a high Zinc content. Not today, even Delvac, Rotella and Delo 400 are reducing anti-scuff additives due to the harm done to Catalytic Converters by Zinc. I used to run Diesel rated oils in my collector cars but no longer.
My oil of choice in those is Valvoline Racing Oil.
Reduction of Zinc is especially critical during break in of a new flat tappet camshaft. The wrong oil can ruin a new camshaft in as little as twenty minutes, Comp Cams has done a lot of research on this due to a large amount of camshaft failures a few years back. Car Craft Magazine had this article:
http://www.carcraft.com/howto/ccrp_0702_break_in_new_cam/post_lube.html that might be of some help.
The lack of Zinc in "older" engines is not supposed to be as "critical" from what I have heard, but in my opinion why take the chance. I have seen 50's and 60's collector cars with 5W-30 run in the engine. Why I don't know. The clearances were more "generous" back then unlike today's engines. When I first started in car dealerships, 500 miles per quart of oil usage was the norm.
Not today. At 500 miles the customer is screaming bloody murder and gets a engine job.