ThanksDealer installed a 21p Stainless steel viper. Have set back plate mounted on 2nd hole. There's technically no break in period for the motor but the dealer advised just take it easy for the first couple hours and don't drive 40 miles down river at WOT until after a few hours on the motor.
Max RPM's i and dealer see on the stock tach is 5800 when the weather/water was 10-15 degrees cooler. water PSI 20-25 at WOT and 8 +/- at idle. Only have a couple total hours behind the wheel and haven't really let er' rip for a long ride yet due to flooding and logs/trash everywhere in the river. Went 1 miles WOT back and forth the past few trips out up and down river. Wanted to spend a lot more time on the Ultrex. Turned 5500 RPMS almost trimmed out in 75 degree water and 90-95 heat /w high humidity. Speed wise I was hitting 44-46 but it was hitting it as I was just about to come to a bridge to slow. There was still room to trim out prior to slowing down. Next trip I'll let it go for 5-7 miles down river. Comes out of the hole like a beast. Motor is ridiculously quiet and uses almost not gas/oil which is nice. XD100 is pricey around here. NFB steering is nice, too.