115 etec on 20’ Seafari

[doug7488]

Hey guys
I know this has been covered to death but I can’t find a definitive answer
Finally put my 1977 20’ Seafari with 2019 115 etec in yesterday

-13.75 x15” 3b aluminum prop from my old V4 110
22mph @ 6000rpm
I think the hub was slipping

-13.785 x17 3b stainless “viper”
28 mph @ 6000rpm

I’m pretty sure it ran 32 mph with the old 110
That’s all the props I had to try

I would think the etec has 25 hp more than the 110

Any thoughts on props?
Thanks in advance!