Budget Build 70 Swinger

To the gentleman whom has that Slant-powered model :

I'm surprised to hear that you car has such high gears in it , considering it's a 225 .
Typically , 3.21 / 3.23 was standard for that motor when combined with an auto trans .
Typically , the high gears didn't appear unless they were specified or with the 1976 Dart Lite / Feather Duster .

3.55's would definitely wake it up , but they may be a little -tight- .
3.21 / 3.23 would be an ideal all-around gearset , that way -- as previously mentioned -- the motor will stay within its power band , which will help with fuel economy ( motor won't lug-along and labour ) and with acceleration .