A 17 is what came on the drive on the boat I pulled my setup out of also, but it was a big old heavy 18.5 ft open bow Larson. Keep in mind the 888 out-drive has a 1.5 to 1 ratio which is the same that they put behind the 351 and 350's. Since the 302 has less torque compared to them it won't need as high pitch as you might think. (140s have something like a 1.98 to 1 drive)
I tried out a 13.5" diameter 23 pitch and got a little over 50mph at 4000RPM. I switched to a large diameter (15.25") 21 pitch and kept the same rpm, dropped to 47mph, but have awesome holeshot and it pulls stuff great. I'm looking for a 19 pitch 13.25ish prop now to see what the max top end I can get out of it.
