slant 6 oil weight

I guess my question is that, will 10-30 be good enough to lubricate a bit stiffer valve springs crane springs similiar to the mopar red 340 springs. Also cam is the loved and hated 292 mopar purple grind. I live in San Antonio,Texas where it gets toasty in summer and winter is mild. Or 10-40 could be a better choice? My driving is for the most part "normal" with spirited jaunts here and there. My engine/bearing clearances are factory. Oil pump is stock pressure/flow. Windage tray and oil slinger are only things I added.