seems the v4s had compression in the 130s, while the v6s usually only had compression maybe up to 110.......the manual doesn't list compression as best I can tell.... I picked up a 1999 V6 150 hp... and the compressions were 93-95.... after I mounted to the boat I took it to a dealership who put it on the dyno and said it was running at 100% of new...as far as putting power to the prop.......