Looking to repower original 1990 Volvo DP 5.7 270 hp engine & drive in 1990 23' Gulfstream. Currently sluggish and inefficient cruise 18-20nts at 15gph. Any suggestions or $$$? Preference bet Volvo or Merc? New Power size 300 or 320 hp? Expectations for new fuel and speed? Closed coolant /...
