...had my first ride in the GT21 yesterday with a borrowed 14x23 blackmax (48 78124 23p) on a 260 sbc with bravo one 1:1.5. My x-dimension is about 14".
Symptoms: straight out of the water, gliding with 2000rpm, clean acceleration to 3000rpm, if you try to rev more strong vibration no gain in speed, trimming up helps to a certain point, revs 3500, you push more starts to spin or vibrate again, needs fine trimming to find a certain point- than it revs to 4500 and gains speed...(about 45-50mph)
Any suggestion with which prop I should start trying? I know it is seat time and experience, but may be you guys have tried or can tell me what I should start with. Thanks