Low oil pressure

Wow, seems like I opened up a can of worms here, lol. I love this forum because everyone is always eager to help the fellow mopar nut. Really good views on this, but let me clear up a few things. This 340 was built for the track, so I think saying it was built with looser tolerances is probably pretty accurate. Just from driving it on the street and having some fun I can say it's probably right around the 400hp mark at the crank. That being said, and after seeing how clean the bores are....I'd say it doesn't have much wear. Which again leads me to believe it was built with looser tolerances. It does get pretty cold in southeast Missouri, so not really driving it much at the moment, but it does get fired up once a week. So going off of some of the posters here I think I will just swap the filter, bump up to some 10w40, check the old oil, and if there's no metal in it I will run it as is. If I get any more reduction in pressure I'll be changing out the oil pump. Also, I've always ran royal purple in my stuff, and will probably stick with it unless anyone has good insight why not to? Thanks to all the posters...you guys are great.