I guess you'll want a nice light weight piston...so That's be a diamond or Wisco. (not cheap) Then it's all on your machine work. for cam a new custom grind would be best but off the shelf the MP 528 solid is a really good cam for a stockish motor. I think you need to decide how much motor you want and how many MPGs you want. I'd think a good tune on a stockish 383 could net 18-20mpg hwy.