Rebuild or different engine?

So I have a 74 dart, bought it about 6 months ago. Odometer is broken stuck at 143k miles. So My buddy and I got into it discovered some problems. Now I'm not mechanically inclined(learning) but my buddy showed me that the "1 and 3" spark plug hole were dead. No pressure. So he said it prob needs a new head. This is the original engine so really old. I'm figuring the engine and trans will need to be replaced soon anyways so my buddy and I are talking about finding a different motor or rebuilding this one. It's a 318 v8. Also I don't have much money so I'm trying to figure the most cost effective solution. My goal with the car is to be a cruiser but maybe have a little bit of ***** would be a plus. Any advice? This was my daily driver so rn I'm walking everywhere. So trying to get it fixed asap!