1965 75 hp V4 Evinrude, need more power.

[danford1]

I have a friend and he wants more power from his 1965 75hp V4 Evinrude. He has three 10 X 10 1/2 props. He is thinking of having one re-pitched to 10 and the other re-pitched to 9 1/2. He wants a variety for speed and pulling power for skiing. It is on an old 1972 Sears 15' fiberglass boat. Not a rocketship nor is it light weight. He builds and races cars and is thinking of milled the heads, perhaps opening up the exhaust ports, advancing the timing, etc.
We know years ago they used to hop up these old Evinrudes to make more power.
What did they do to them and what can we do to his easily?
Any and all suggestions will be welcome.
Thanks.
Danford1

 

[tashasdaddy]

Re: 1965 75 hp V4 Evinrude, need more power.

well before doing anything he needs to find out what his wot rpms are. i would say they should be around 5500. they originally were in the 4500-5500 range i believe.

 

[DJ]

Re: 1965 75 hp V4 Evinrude, need more power.

You're not going to get much out that tiny little gearcase. It can only bite so much water, regardless of what is driving it.

 

[danford1]

Re: 1965 75 hp V4 Evinrude, need more power.

Are you saying the gear case is weak? Or are you saying something else? What does you can only get so much from the gear case mean exactly?
Thanks.
Danford1

 

[Evinrude Boater]

Re: 1965 75 hp V4 Evinrude, need more power.

It's small, size matters.