Re: 4.3 vs 5.0 and Boat Size
There are too many factors for how general your question is. A 4.3 can come in MPI or Carb as can the 5.0. An 18 footer can be 2100lbs for a budget model or 3000lbs for a premium version. A 21 footer, if they are counting the swim platform in the LOA, can be 2900lbs for a value brand or 3500lbs for a premium brand. Give a couple specific comparisons and we could tell you.
The easy ways to increase power in a 4.3 are to change out the prop. If it is a carb 4.3 you can change to a 4bbl carb and new intake. For some people that is an easy process completely ignoring the cost. A carb/intake swap on a 4.3 can gain you in the neighborhood of 20hp and get close to the MPI hp.
