1973 225 valve adjustment help!please!

If you've got a "knock" coming from the "front" of the engine at idle, you might want to check the oil level. Wouldn't be the first slant to "knock" because it had been eons since anyone had added a "little" oil. These motors usually survive conditions and owners that would have stopped engines with bowties and blue ovals on their hoods dead in their tracks. You'd be amazed what oil on the dipstick does to "quiet down" a noisy slant.
I agree with the above posters about the engine running valve adjustment, .010 on the intake and .020 on the exhaust, engine warm and idling gets you there every time. Lay a shop rag over the distributor if you're worried about a little oil splash.
One particular valve loosening up every couple of days might mean a worn out rocker arm adjustor or it might mean you're loosing a cam lobe. Worn lobes don't give the smoothest idle, but even a completely round one probably won't kill a slant.