Hey Craig, how ya doing, good to see you using the props , my X dim on my 20 is 17 3/4. how much are you trimming up while running as well? what are the rpms range for your engine and are you closed to peak?, meaning if your engine hits its sweet spot at 5700, and youre only turning 5500, you are leaving speed on the table, maybe consider labbing the set that gets you closest to your rpm range and go from there...Rob

see if this helps http://www.boatfix.com/merc/bullet/93/93_19.PDF

Rob nice to here from you I just finished reading you build on your cig congrats that is awesome good for you now I think you need to go back and work some more wow lol.My boat is doing well I am running 85 at 5400rpm but my motor was built to spin to 6000 not that I want to go there in rpm but I too took 4 years to my build I am running 350 mpi and a 2.8 whipple and loving the whipple but the motor is coming out and we have to put on the dyno and do some work on more boost and trimming and fine tunning.I'm also going to raise my x to 17 1/2 that should put me in the 90s and then try to spin the 29 or 31 I have will keep you posted.I'll put some picks up later.thanks craig