Last Sept. I bought a 1990 24' Python that supposedly had a 10 hr 468 in it. We couldn't run the boat on the lake as the lifters needed adjusting but with all the parts I was getting the price I was paying if it was junk I could sell the parts and get my money back. I replaced the transom, rebuilt the motor, had a leaking header repaired, redid all the guages and most of the wiring as well as repowder coated most of the metal. I had the motor dynoed and made 450hp with a .60 over gen 6block, scat rods, SRP forged pistons, stock oval ported heads, and Bob M. custom hydraulic roller cam. Put everything back together and run it 3 hrs and a valve seat drops and eats 5 pistons. I redid the motor using all the same internals but I upgrade to 320cc World Grumpy heads and edelbrock rpm intake. I never dynoed this motor but I am questimating it around 500hp. The best speed so far is 68 with a unknown 25p stainless prop that I have to trim the hell out of to get the boat out of the water. Winter plans are for new interior and to get rid of the carpet and get a 25 Mirage plus. The boat originally had a 502 with a blower through the hatch thats the reason for the oval cover in the middle of the hatch. Supposedly, with the blower motor it would run 92???? The boat came from SC so some of you might know more history on it than me. Just a few pics after it was all completed.
Last edited by cdail28590; 09-08-2011 at 11:26 AM.
My 1990 24 python would run 70 with the first generation 502/390hp merc and bravo
Trimmed way up I am running 4800 rpms. The cam was designed to pull to 5200. I still have some prop work to do.
those numbers are showing about 10% prop slip so if you can get up to 5200 you should be in the 75 mph range. I think your HP numbers are a bit low but it looks like you have all the right stuff to make that kinda power.
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I looked at your pictures and rocognized your boat from years past on Lake Murray. Larry AAron's used to own that boat and is now deceased. He boated with my uncle who also had a 24ft Python. My Uncle"s boat ran 76 on the speedometer with a 365hp Mercruiser. Larry was alot faster with the blower motor but had a hard time keeping it running. It was aloud boat with the headers in the day.
The boat was from Lake Murray and it had a sticker on the back that said Larry Land. I was told by the guy I bought it from that Larry had died and the boat sat for a long time when he got it. He ran with engine troubles and traded the blower motor for a rebuilt 468. He never broke the cam in correctly which subsequently caused me to redo the motor with a newer block and better parts. The 450 hp on the dyno was with the stock Oval ported heads. I didn't dyno the motor after putting the World heads on it but I figured with the larger cc and flow that they should put me close to 500hp. Also forgot to mention I still have the timing turned down as the motor only has 7 hrs on it and I want to break it in good before turning it up. It's still loud but I'm used to it now but after a long ride your ears ring and its even worse riding in the back seat. Its a lot better now than when I got it and I am still working to make it better. I like for all my stuff to be right.
My uncle used to run a Yamaha outboard prop that had a lot of rake in it on his boat. I have some 3 blade 25 mirage props you can try.
How did your uncle's boat handle with that Yamaha prop? I do have a single external hydraulic steering. I would be interested in trying your 25's. Just PM me on arrangements. I have 2 atricles from Hot Boat magazine where they tested the 24 python. 1 was a stock 502 with a 1.5 bravo and a 25p Mirage and it ran 75 on the radar and the other was a 454 with a blower on it with a 1.36 bravo running a 25p Mirage and they stopped running it at 80 as it was dangerous. So it seems the 25p Mirage is what came from the factory on most of these boats. Thanks.
Last edited by cdail28590; 09-12-2011 at 10:44 AM.
I ran the boat this weekend and actually had the GPS on the boat to get accurate #'s. With a 3 blade (no name on the prop) 25 p it ran 68.3 @ 4800 = 10% prop slip. I then put on a 25 p 4 blade vengance prop and it ran 69.8 @ 4600 = 4% prop slip. My prop slip #'s seem to be good but I don't understand why I can't pull more rpm. My buddy was running beside me in a 24 Fountain with a stock 502 with a different cam and CMI e top headers and he turns a 28 left hand Bravo to 5200 rpm. My motor should be making more power than his but it won't turn up. His boat runs around 75ish. I tried his left hand 27 hydromotive but I didn't even run it over 45mph as the boat had a terrible lean and you could trim it up to the get the lean out of it but it was just a totally uncomfortable feeling driving it. This boat definately does not like left handed props. It did come out of the hole pretty easy with the 27 on it. I still have the timing turned down to 30 so the plan is hopefully if the weather is nice this next weekend I will use the same 25 4 blade vengance prop and turn the timing up to 34 and see what my rpms do.
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