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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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Posted: February-01-2005 at 12:21pm |
Question for those that have a modified 351w engine.
I'm looking at changing to a ACME 612 or 470 which is a 12.5x15.25 and 12.5x15 respectively. I currently use a 13x13 and turn to many RPM's. Have any of you changed props and if so what did you change to? and what change did you see in RPM and hole shot? Now I'm not interested in hearing about the 540 it just won't get the job done. And I'm not interested hearing from you if you have only changed the intake and carb. I'm looking for Fans that have changed cams, done head work, and have balanced engines that produce over 300hp. That way it will be a close comparison to what I have. |
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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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Also does anybody know where to buy ACME props for less than $245.00 new?
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SS 201
Senior Member Joined: October-20-2003 Location: United States Status: Offline Points: 232 |
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My engine produces 459 hp & 371 lb torque at 6500 rpm.
However I choose to run in the 5000 rpm 5500 rpm that produces 407 hp, 428 torque, 5500 rpm 439 hp 419 lbs torque. Torque for me is the answer, not hp. With that being said I use a Custom Menkens 12 X 15 3 blade steel turns 5200, a Johnson 12X 15 cup turns 5200. I have a Johnson 11/1/2 four blade SS also turns 5200 rpm. I also use nitrous 150 hp kit that adds 700 to 1000 more rpm with the same props. A Menkens prop is $850.00 a Johnson wheel is about 300+ $. I have been useing both for years and for the dollar Johnson beats them all in my opinion. |
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Darrel
Senior Member Joined: June-16-2004 Location: United States Status: Offline Points: 340 |
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Where can you get a new ACME for $245? That sounds like a good price.
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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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Bill thanks, for the info
you make me jealous with all of the goodies you have bolted on. Do you still ski behind that beast. I really don't know what the torq of mine is but I do want to get back to the 5-5.5k rpm range from the current 6K it runs now. Do you think that a 13x14 would be better than choice than the 12.5x15? I believe there is some cup to as well maybe .080. A good friend of mine is a buyer for a group of independant boat builders and he sells at cost to me so I can get a pretty good deal on about any think. |
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SS 201
Senior Member Joined: October-20-2003 Location: United States Status: Offline Points: 232 |
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You welcome,
If your wheel now is 13X13 with all that power you would only come back about 200-300 rpm. The only reason I cut back on the diameter is to take the twist off the boat. Now I am not pulling skiers so the equasion changes a bit. I have a couple of 4 blades cut for my hull you are welcome to try. However a good cupped 13 X 14 works well If you call Eric at Johnson prop 800-359-9730 ,tell him Bill Burgess told you to call.He will work with you, as you can send the prop back and forth to obtain your desired objective. he is a ex racer himself and understands your hull from years of experience. |
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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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Thanks again.
And I'll give Eric a call |
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SS 201
Senior Member Joined: October-20-2003 Location: United States Status: Offline Points: 232 |
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Anytime,
Eric is a good choice, as I said he will work with you. If you want e mail me at wburg69@yahoo.com with all your engine mods and carb selection, I can give you a close hp and torque curves, you can work from there. Include you cam card specs if possible. I can put thru my dyno program. BB |
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64 Skier
Senior Member Joined: February-08-2004 Location: United States Status: Offline Points: 415 |
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Sorry to poach on a post but..SS201... Got a question for you??? Since you helped fix my carb, I thought you might be able to help with the following:
My engine is an old ('63) 289 with the solid cam. It had a 2bbl carb. I rebuilt 030 over and put a 4BBL with a performer intake. The heads were also reconditioned and the guy said the previous owner put big chevy valves in the original heads. I have square BARR Marine exhausts. I like the old solid cam, but don't know the spec's? Is it mild or wild? My books say the solids in '63 were in Sheby engines so I assume it's fairly wild but in the water, I can't tell cam lope from exhaust gurgle! I'm running 020 lash. I've seen 351W heads with 4V in the casting so assume some difference between the 2V. I read where the 2V heads have smaller ports than the 4V heads and my engine had a 2bbl carb. Any help appreciated! |
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SS 201
Senior Member Joined: October-20-2003 Location: United States Status: Offline Points: 232 |
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Ill probably hang myself out to dry here as this very touchy subject. Without the cam card not being degreed or sent to a cam grinder, it's tough to say pure spectulation.Take a vacumn reading and if there no noticable leaks.
A stock to a mild cam should give you at least 15 inches of vacumn, and the lobe centerline which also gives you a wild to mild idle.Also for that matter can tell you what is going on in the engine. However most performance marine cams are built for torque range unless it turns over 5250 RPM. The greater the duration the higher the range. If you are runing 20 thousands valve pretty much says it a single pattern cam. Now here it get's trickey with a solid lifter cam you can change the valve lash to be less to get more power or vs versa. However unless you know how much valve clearance be very careful. Also can change rocker arm ratios and make a different cam profile. It makes the to believe is is of different grind.Again unless you know what clearances valve to piston is, don't do it. |
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64 Skier
Senior Member Joined: February-08-2004 Location: United States Status: Offline Points: 415 |
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I did change my intake lash from 020 to 018 and it pulled a slalom skier noticeably harder. The top end dropped 2 mph. That lead me to think I put too much intake on and lost torque from idle to 2500 RPM.
For low end torque (skiing and getting this narrow hull on plane), are all these bolt on HP schemes working against us? Seems like it's the exhaust we should focus on and I should have been porting my heads rather than buying new parts??? |
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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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Bill
Here is what I know about the engine. It's a 1979 351w block with D70E-AB or D70E-DC heads. edlbrock performer intake, custom comp cam with 112 lobe seperation .218 int/.224 exh duration @ .500 lift .476/.481 gross with stock rockers. Now for what I don't know. I'm sure the block and/or heads have both been decked and the cyclinders are bored oversize .010-.030" ? most likely closer to .010" but I'm sure we'll have to work backwards from the compression to figure cyclinnder and head volume and compression ratio. Put it's cold and snowy here in Indiana and it will be the end of march beginning of april before I can crankit over to get the compression reading for each cylinder to get and average compression to use for calculations. I was told with the cam the engine should produce 305-315hp. |
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Bill B
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Ok, now give me he intake manifold type ex single or dual plane and carb size ex 600,750 CFM. Heads are stock,or have some work done, such as three valve angle job etc. You are running stock exhaust with mufflers?
I will be gone for a couple days and will get back to you |
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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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Bill,
see if this will help. edlebrock performer dual plane intake holley 4160 single inlet 600cfm rejeted w/#71 three angle valve job with high rev components double roller timing chain approx 8.75:1 compression ratio Block's been square decked main saddle align honed torque plate honed cyl. computer bored cyl's (at least .010" over)Crankshaft balanced to .5 ounce/inches pistons/rods to .5 to 1 gram. |
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