318 replacement cams....

I'm with Del on this one; I would add as a reply to your question, as long as your stem seals are good and you're not using a cam requiring high seat pressure you'd probably be just fine. I suspect there are members here who slid RV or Comp 260 high energy grinds in their 40 year old engines with no adverse effects given proper tune and serviceability. I would also recommend a new timing set if you plan on swapping cams.

EDIT: Something like what Del mentioned above, a stock spec 340 grind, or a Summit K6900 cam kit would probably be about right for a stock 318 w/4bbl intake.