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Splash
10-26-2000, 11:33 AM
I recently purchased a 1988 Z21 with a Mercruiser 7.4L with 330hp. I'm running
a Mirage stainless 14.5" 23P with a Bravo stern drive. I have been told that the max rpm is 4600 for that motor and I'm running about 4800 @ 61mph. After doing some research it looks like the Bravo I 4 blade 24P should help the top end as well as bring the rpm's down by at least 200. Is anyone running this prop or any input on Pitch/Speed/3 blade versus 4?

GeneD
10-26-2000, 11:40 AM
You know, I know someone that just purchased a Z21 with a 454 and Bravo.
Could you be him? Or his buddy?
Your profile is not complete.

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GeneD
007
Melbourne, Florida

GEOO
10-26-2000, 11:52 AM
Four blades have less slip then three blade, therefore your cruiseing speed can increase. However three blades are usually faster top end. You may want to have a prop shop add some cup to your prop. Cup will enable you to trim up higher and will bring your rpm's down 100-150 rpm's. GEOO

BigGrizzly
10-26-2000, 10:36 PM
My son has a 22ZX double stepper with the 454 small out putand uses a Bravo1 prop. this prop is a 24p prop and runs about 4600 rpms 61 on gps