Volvo penta duoprop selection

[Lazyboater]

Hello
I'm new here and stumped on a subject.... Prop selection. I have a 94 200 with the 572 and 290 dp with 1.95 ratio. Right now I'm running B6 props and only getting about 44mph at wot. I'm thinking of going to B7's to get more speed. Any help will be thanked.

[jhnmdahl]

What rpm are you at with your current setup wide open?

[Big Block Power]

We need to have your wide open throttle rpm to really help you. If you go up in prop pitch you may go faster or may go slower. Plus you will lose your hole shot. Unless your bouncing off a rev limiter you prob won't be gaining.

[cmattj]

Introduce yourself in the new members section. We’d like to hear about your Cobalt.. see some pics. Other members with your combo can chime in.

You may want to correct your engine description to a 5.7 although if it had a 572 we’d be wanting a ride!!

[Big Block Power]

Introduce yourself in the new members section. We’d like to hear about your Cobalt.. see some pics. Other members with your combo can chime in.

You may want to correct your engine description to a 5.7 although if it had a 572 we’d be wanting a ride!!

You got 5.7 out of that. Wow I missed that one. But I had no clue what engine it was. I'm like heck I would take a 520 but a 572 Volvo had it going on back then.
I'm sure he's sick of telling everyone thank you after they say that's a beautiful red boat. After he just spent 2 weeks buffing it.

[cmattj]

I'm sure he's sick of telling everyone thank you after they say that's a beautiful red boat. After he just spent 2 weeks buffing it.

You get used to crowd gathering. I may change the name to simply..

“thank you”

[Lazyboater]

Sorry, I'm new to boating just got a very good deal on the boat... wot is 4600 to 4800.... I didn't want to blow engine..lol. There are alot of things i need to do with this boat to make it right. But I will send pics of what $500 can get you in Texas. Engine is sound.

[Big Block Power]

Sweet. 5.7L 2 barrel carb. Is my guess.
Sounds like your right in line if that's what your hitting for rpm.

[cmattj]

Looks good and I like that it does say 572. Which is s sb Chevy 350ci convered to liters. 5.7 Adding a 2 barrel?? Cool cover!!

Yes more pics and we will determine if you should make a change.

Sounds right now and adding pitch will give you cruise speed but may strain on top end

[Lazyboater]

I was thinking on adding 4bbl carb to help with prop selection. If that helps... and thanks on explaining the 572 for me....duh

[NautiGirl]

I'm sure he's sick of telling everyone thank you after they say that's a beautiful red boat. After he just spent 2 weeks buffing it.

You get used to crowd gathering. I may change the name to simply..

“thank you”

[Big Block Power]

I was thinking on adding 4bbl carb to help with prop selection. If that helps... and thanks on explaining the 572 for me....duh

Then you will need a new cowl. 574.
If your going to do that you mine as well change the cam. You could get in touch with nola's guys they would know which one to put in there. I would leave the valves alone you never know they could start to stick if you have a good but shotty machine shop do it.

[Lazyboater]

But for now I want to know if anyone knows the difference of pitch in B6 props and B7 props.

[Big Block Power]

But for now I want to know if anyone knows the difference of pitch in B6 props and B7 props.

Yea one pitch. lmao

It's like a mercury 24-26 pitch just in Volvo secret code.
200-300 rpms prob.

[cmattj]

Yea one pitch. lmao

It's like a mercury 24-26 pitch just in Volvo secret code.
200-300 rpms prob.

Tricky Swedes