Prop Help 454 MAG?
#1
Thread Starter
Registered
Joined: Feb 2008
Posts: 148
Likes: 0
I have an 89 Century Ultra I with a 454 MAG carb. and Bravo outdrive. Its stock except stainless marine headers and risers. I'm currently running a 23P 3 blade mirage prop, peak rpm is 5200 and I can get about 64 mph by the speedo in perfect water. Could I get a little more top speed with a different prop or is this ideal. The valve cover says 4800-5000 peak rpm I believe. Thanks for the help!
#3
Registered
Joined: Aug 2005
Posts: 812
Likes: 1
From: Ray Twp. Michigan
I have an 89 Century Ultra I with a 454 MAG carb. and Bravo outdrive. Its stock except stainless marine headers and risers. I'm currently running a 23P 3 blade mirage prop, peak rpm is 5200 and I can get about 64 mph by the speedo in perfect water. Could I get a little more top speed with a different prop or is this ideal. The valve cover says 4800-5000 peak rpm I believe. Thanks for the help!
#5
Registered

Joined: Feb 2009
Posts: 8,356
Likes: 1,515
From: NW Michigan
I think you have the right prop. It certainly doesn't hurt anything to be running a couple extra hundred RPM on flat water trimmed out. As you know when you have to tuck the drive in due to rougher water those extra R's come in handy. You can always try another prop however I doubt very much you'll gain anything and lose a lot of bottom end and mid range.
I am not real familiar with all the particulars of your boat however your speedo seems to be pretty accurate assuming your bravo is a 1.5. Regardless of what it says your set up seems just fine.
John
I am not real familiar with all the particulars of your boat however your speedo seems to be pretty accurate assuming your bravo is a 1.5. Regardless of what it says your set up seems just fine.
John
Last edited by getrdunn; 07-06-2009 at 09:25 PM.
#10
Going from a Mirage to a Mirage plus will lower the rpm's by about 150 - 200. If you try to go from a std mirage 23 to a mirage plus 25 you will drop to about 4600 and the boat will be very sluggish in the acceleration dept and probably loose some top end. Look for a Plus 23 or a non plus 25 to try or possibly a Bravo 1 24"
Good Luck
Good Luck





