actually, thats an old urban legend. The bores are the same depth. A 289 makes a fine stroker, not that a 302 wouldnt do as well.
Your combination (you didnt say what gears you have, I assume the stock 2.80) says you need low end and mid range. I suggest ported 351 C or DOOE heads w oversize valves for a strict budget, or Darts/Roush or perhaps E-boks if you have more dinero. Stick with a dual-plane intake and about a 600 CFM carb, vac secondary.
Headers are a must, long tubes if you can fit them in. If you want low end and midrange, dont overcam.