52mph WOT! What gives 25' Others get 70+
12-05-2012, 10:17 AM
#42
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Great example of speed BS. There is no way a 26 pitch prop turning 4800 rpms is going to give you 78 MPH. I also doubt the engine is making 525 hp at 4800 rpms, that is unless you're running a blower on it. In order to make more power you need to turn more rpms or increase the displacement.
12-05-2012, 10:19 AM
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12-05-2012, 09:05 PM
#44
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yes, he lost cam specs. Says its a crane cam, whoooppee doesnt help/ The valves are 2.17 and 1.72. I cant find gear ratio on outdrive, any place special to look? Also It does have the stock manifolds but they are stainless. What kind of headers or manifolds can I use to free up HP and still use the Corsa switchable exhaust. The pipes are like 5 inch all the way to the fiberglass and then 4" tips. I bet it is built for 6000rpm and up, you guys may be right but damn 52mph is awful. That 4 blade 23p has to go first? Should I get an Edelbrock torker intake and headers?
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12-08-2012, 09:55 PM
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2.19/1.88 I am sorry, this is the correct valve size. I did it from memory but I looked again at what I wrote down. They are large rectangular port heads 990's is what they are called. The shop told me the carb is going to be way too small. Id need a HOLLEY 850 dual feed. I just dont know. If the stainless manifolds are killing a lot of HP what ones do you guys recommend? Would regular old ceramic headers work haha. It would be way to hot in the engine compartment.
12-08-2012, 09:59 PM
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A merc 502 with 425 hp runs the same carb and so does the 454 and both push the boat well over 52 mph. There is a report posted on this boat in the general question section and with a stock 454 Mag the boat would radar at 60 MPH. There was one guy that claimed his boat hit 72 on the GPS but I don't believe it, I'm going to believe the magazine article. So with that said 52 mph would be right around 270 hp. The stock prop was a 23 laser II, so a 23 4 blade is two much. He needs to either run a 21 blade or a 23 3 blade and then see where he is at. Then yes- he needs a holley 800 cfm carb. Seeing that a car guy built this, I'm betting we are going to see that it has a cam that produces power past 6000 rpms. This would also add to the problem. Then on top of that I'm willing to bet its running the stock exhaust. The exhaust, prop, and carb might be good for an 80+ hp drop but I think the biggest problem is going to be the cam that was installed. However these are all guesses until we get the engine specs. With 525 hp this boat should be right around 70-72 mph.
I see what you are saying, I have a combo of crap wrong. The cam was a comp xtreme boat cam. Thats what he told me. The 4 blade 23p is wrong then? The carb is too small, and manifolds suck, haha They are a stainless aftermarket but look stock to me. But new!
12-09-2012, 09:00 AM
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