302 top speed?

[chris in va]

I've been experimenting with my Pro Pulse prop. It seems to run best around 19-20 pitch, but just curious...what's the top speed I can expect with a 2-bbl carbed 302? I've yet to crack 48mph or so which seems fairly slow for a V8. <br /><br />In case you're wondering, I also tested it with a normal 3 blade 17 and 19. It has a full tune up and is running great.

 

[Dunaruna]

Re: 302 top speed?

It depends on boat weight and prop pitch. My 302 redline at 5200rpm and my top speed with a 19inch is about 35mph but i,m pushing a 2.5 ton boat, with a 17inch top speed was around 28mph. I've had ski boats (around 1 ton) with 60mph top speed running a 307. Any standard v8 will rev to around 5000rpm, the prop it is turning and the weight it has to push will determine top speed. Then of course there is gearing.......

 

[chris in va]

Re: 302 top speed?

I should have elaborated. This is with a 19' Caravelle bow rider weighing 3600# with the trailer, so I'm guessing about 2800#? The rev range is supposed to be in the 4300-4800 rpm area. I'm wondering too if the whale tail is lowering the top end some...but dang it sure helps low-end planing!

 

[Doug Durako]

Re: 302 top speed?

The whale tale is going to slow you down when you trim out for speed---my guess is you are losing 5-plus mph at wide open throttle. Are you using GPS for your speed measurment?<br /><br />Is your drive a newer Merc Alpha design?<br /><br />Also, your Caravelle hull design may only allow you to get about 53 or 54 mph max, trimmed out, before you start to suck air and over-rev the motor.

 

[JasonB]

Re: 302 top speed?

I'm running a 19' boat with a 2bbl 302 and my top speed is about 44. My hull is a very deep V which slows me down, but the weight is about the same. That speed was with 26 gals of gas and 3 people on board at the end of last season.

 

[WSUDERMAN]

Re: 302 top speed?

Its not quite the same, but i have 305 with edelbrock carb & intake, boat is about 2800# as well and i have seen 51 mph GPS. this is at about 500 Feet Altitude with 4 people and 15 gal of fuel.

 

[SS182]

Re: 302 top speed?

We have a 305 merc on our '93 Wellcraft 18' bowrider. Pre-hyrdofoil we got just shy of 60 mph with a 21' 3 blade ss prop. Same prop with hydrofoil brings us down to the 54-55 range. Just something else for you to compare to.<br />SS182

 

[chris in va]

Re: 302 top speed?

Hmm, that's very interesting. Didn't know the hydrofoil would slow it down *that* much. Maybe I'll take it off and experiment a little more. <br /><br />So, what do I do with the holes left behind on the 'cavitation' plate?

 

[akriverrat]

Re: 302 top speed?

touch up with paint if you didn't do it when you drilled them.