I know there are alot of opinions/suggestions out there. I think mine was the most cost effective with least labor. Here is what I did:
1957 235. dual carbs. bone stock 3 on tree transmission. All I did was change the ring and pinion gear in the rear end (Yukon gears). I now have a 3.38 rear and do highway speeds.(60-65mph) can do 70+ but RPM's get significantly higher once I push it past 65. here is the link for the gears:
http://www.classicparts.com/1955-62-Rear-End-Gears-338-Ratio/productinfo/93-513/ GOOD LUCK
