Oil pressure problem?

I was worrying about the oil pressure last weekend when I took my very stout 340 previously track only car down the country road to the local pool bar. Was seeing 40 PSI at 2000-3000 cruising down the road. 20W-50 with the break-in oil (with cam lube) after a hotter cam was just installed. I was wondering if the oil filter was clogging up.

I have 6 qts of green 20W-50 oil. May change out the oil and filter but now I gotta worry about the darn zinc. Additive?

So worried about blowing this 340 that maybe I should just build a stroker from one of the 360's I got with the car and leave the little 340 alone for now till I can see exactly what's in it.