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john_t

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"I rebuilt the single 327f in

"I rebuilt the single 327f in my 1975 28' CC Catalina from the crank up, bored to 350ci. Its running 6100rpm (29mph)at full throttle. Too much right? My thought is to add pitch to the prop to bring the rpm down. Any thoughts as to what the prop should be?"
 
"Ayuh,......

You need to ge

"Ayuh,......

You need to get your WOT, Down to about 4400/ 4800rpms.........

Btw,..... 327s,+ 350s share a 4" bore,....At .030 Overbore they would be a 332 or a 355......."
 
"John, do You have access to a

"John, do You have access to a photo tach, or a tach tester? those numbers just don't seem right."
 
"No, but the tach is new and I

"No, but the tach is new and I replaced the original distributor with a new HEI, where I am picking up the signal. It idles at about a thousand rpm.
The prop came with the boat which was in pretty rough shape. I don't have a lot of confidence that it is the correct one. I think the diameter is correct (its about an 1 1/2 from the hull) but I am unsure as to the pitch.
I stand corrected, its a 332ci not a 350."
 
"John,

Consider yourself lu

"John,

Consider yourself lucky for running that motor at 6100 RPM and not blowing the motor. I am having the same issue except the other way around. I dont know what size props I have but I am running 20mph at 2500rpm. I need to pitch down like 4 inches. 2 inches of pitch give you 400rpms. So figure you need to pitch up about 4 inches. Also keep in mind of fuel economy. I would recommend to maintain 4500 WOT. Saves the chevy!

Use these website to help you configure.

http://www.rbbi.com/folders/prop/propcalc.htm"
 
"Neat program, Louis--it's

"Neat program, Louis--it's a keeper! And running 20 mph at 2,500 rpms sounds okay to me since that is exactly what mine runs.

John: You probaly need to add a couple inches of pitch to the prop--that'll improve gas mileage as well as save Mr. Chevy.

Jeff"
 
"You may want to look at my Ga

"You may want to look at my Gas, Prop Pitch vs. RPM topic. I need help on my matter. I am assuming that i have 15X17 and I should be using 12X11. I am looking to get about 2MPG with both the motors combined. Any suggestions?"
 
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