To me, if you are going to rebuild a 302, it is much cheaper to get a 302 crate engine (gofastparts.com) are an excellent resource for crate engines (all makes) and typically saves about $1500 when comparing to a conventional rebuild.

The 302 is not a bad engine, just choked up on small head ports, depending on the year, your hp rating will be about 150-175 and tq about 250 to 300. Given the weight of the fairlines/mustangs (about 2800-3200 lbs), your truck is not that much heavier (about 3500) which the 289 hipo will have no trouble handling especially considering the fairlanes/mustangs typically had 3:55 to 3:89 gears in the rear ends (standard had 2:70's). The reason for myrecommendation for the 460 as compared to the 351..both really good truck engines but a lot more power with the 460 and same mpg.