Another data point I can recall from the past, not boats but cars.
2 of our family vehicles
1972 Chevrolet Impala 5.7 V8, 2bbl Rochester, 3 speed GM Hydramatic
1975 Olds Delta 88, 5.7 V8, 4bbl Rochester Quadrajet, 3 speed GM Hydramatic
the Olds weighed a few hundred lbs more than the Chevy, not...