Checkmate 242 Convincor with Built 502

[Cockeyed]

I need help identifying what prop to use. Here are the specs of my motor, please offer any help you can. I currently have a 25P Quicksilver Mirage & I'm not getting the top speed I feel the boat is capable of, specs are as follows:

502 Bored 40 over stroked to 540
Dart Pro 1 Heads w/ ARP Studs
Quick Fuel 1050 CFM Carb
RPM Airgap Intake
High Performance Rings & Rocker's
SRP Flat top Pistons
Bravo 1 Outdrive
1.5 Gear
9:1 Compression
Estimated 650 hp
Estimated 740 Torque

I've been told several things, typically run a Mirage 29P or 30P, and one said a Bravo 1 28P or 30P 4 blade prop. Anybody got suggestions or recommendations?

Thanks,
Ken

[Gordo]

I'm thinking you're pretty close to my setup, and a 28p Bravo 4-blade prop would be a good start?

[Cockeyed]

I'm thinking you're pretty close to my setup, and a 28p Bravo 4-blade prop would be a good start?

Thanks, what kind of top end are you getting, and how many RPM's?

[Dave M]

What RPM are you propping for? The builder should know that.

What is your current speed and RPM.

[Gordo]

A lot of variables, (air/water temp, load, etc.) but 83mph @ (I think) 5200ish.
Turning a Lab-finished 28-P Bravo IV blade

[Cockeyed]

What RPM are you propping for? The builder should know that.

What is your current speed and RPM.

Well the motor hasn't been broken in fully, so I was told the RPM's would rise between 600-1000 when the motor finally settles, we got 5200 RPM at 64 MPH, but will get some RPM's after adjusting the timing better. Everything I've read shows that I should be getting 80-85 mph.

[Cockeyed]

A lot of variables, (air/water temp, load, etc.) but 83mph @ (I think) 5200ish.
Turning a Lab-finished 28-P Bravo IV blade

You're right, sounds like a similar set up as I think that's about where I want to be...Thanks!

[Dave M]

Well the motor hasn't been broken in fully, so I was told the RPM's would rise between 600-1000 when the motor finally settles, we got 5200 RPM at 64 MPH, but will get some RPM's after adjusting the timing better. Everything I've read shows that I should be getting 80-85 mph.

Based on those numbers, your slip in 22%. Is you prop in decent condition? I'd try a Mirage+ or Bravo 1.

My previous boat, 24 Superboat was turning a 28P bravo 1 @5000 RPMs with only 425 HP, 78 MPH.

[ThisIsLivin]

I have a 522 with just over 600hp in a Velocity 280 and with the the Bravo 4 blade 28p I run 82 at 5200 without any trim, the prop blows out. I have a 27p Hydro-Motive 4 blade cleaver that runs mid 80's at 6000. I talked to Mercury Racing and they recommended a labbed 5 blade 30p at 15" diameter.

[Cockeyed]

Based on those numbers, your slip in 22%. Is you prop in decent condition? I'd try a Mirage+ or Bravo 1.

My previous boat, 24 Superboat was turning a 28P bravo 1 @5000 RPMs with only 425 HP, 78 MPH.

I have a 522 with just over 600hp in a Velocity 280 and with the the Bravo 4 blade 28p I run 82 at 5200 without any trim, the prop blows out. I have a 27p Hydro-Motive 4 blade cleaver that runs mid 80's at 6000. I talked to Mercury Racing and they recommended a labbed 5 blade 30p at 15" diameter.

Thanks for the information guys. I'm tempted to contact BBlades & try there test program, I've seen some others post that they have had great results with them. But since the consensus is a 28P, I'm thinking about trying the 30P just to see what kind of results I can get & how well it can push it...

Anybody have any experience with BBlades & tried there loaner/test program?