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What to expect out of a 496 CI

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Old 04-01-2009, 10:14 AM
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i am ordering the sticks today from bob. he needs the flow results and i'll let him decide. on the CI route i go. years ago we had good results with the oval ports up to 496 CI however i'll have to dig for the data.
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Old 04-01-2009, 10:32 AM
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Old 04-01-2009, 10:00 PM
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Originally Posted by Young Performance View Post
Without going crazy and having a reliable piece that can run on pump gas, you can expect about 1.20 hp/ci with aluminum heads and about 9.5:1 compression. With a little more compression and a decent size cam, you could expect to see 1.27-1.29 hp/ci. Hope this helps, Eddie
I guese my builders are not as good ! My dyno results were 500 hp max and 600 trq max. peaks around 4k (I think) 496 ci. Dynoed wet with stock merc center dump and water pump, sea pump and alt.Dart alm. pro 1s 310 cc elderbrock air gap 9.3 or so comp. msd dist. Dont have cam specs right now 750 demons .Should I be worried Can I get more or just build 540s they seem to be getting 700hp plus or so out of only 40 more ci what gives?
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Old 04-01-2009, 11:39 PM
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The heads being used at this time are the worked over 049 casting's oval port 2.19's and 1.85's by Valako. We get these things to flow well and considering were under 500 CI and staying under 610 to 615 lift they will work fine. I used many of the dart recs and use to wedge them at this CI. Trq. and dyno results are amazing.
Have you talked to Jim Valako about the projected HP or his thoughts about going to 496's? When Jim and I did my 470's I was contemplating the same thing as you. We decided to stayed with the 454 base and I decided that I would put that money towards bigger cubic in engines in the future. We put together some solid roller 470's with his ported heads that put out 590HP.


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Originally Posted by redcorvetteman3 View Post
I guese my builders are not as good ! My dyno results were 500 hp max and 600 trq max. peaks around 4k (I think) 496 ci. Dynoed wet with stock merc center dump and water pump, sea pump and alt.Dart alm. pro 1s 310 cc elderbrock air gap 9.3 or so comp. msd dist. Dont have cam specs right now 750 demons .Should I be worried Can I get more or just build 540s they seem to be getting 700hp plus or so out of only 40 more ci what gives?
Those are nice numbers for real world wet dyno #'s running accessories. Remember dyno racing proves nothing the real dyno is the boat and those #'s are read on the SPEEDOMETER!
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Old 04-02-2009, 02:46 AM
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Originally Posted by redcorvetteman3 View Post
I guese my builders are not as good ! My dyno results were 500 hp max and 600 trq max. peaks around 4k (I think) 496 ci. Dynoed wet with stock merc center dump and water pump, sea pump and alt.Dart alm. pro 1s 310 cc elderbrock air gap 9.3 or so comp. msd dist. Dont have cam specs right now 750 demons .Should I be worried Can I get more or just build 540s they seem to be getting 700hp plus or so out of only 40 more ci what gives?
I think your carbs are too small and you should be making more HP. Your stock exhaust is choking the engines and most likely the cams are on the small end because of the stock exhaust and reversion concerns.
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Old 04-02-2009, 08:38 PM
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Thanks guys Im going to look into headers next but wow...there damn near as much as motors.They say headers are better so I thought I would by headers even though I may not realy need them now but so as not to double buy if I ever go to bigger ci later.Any thoughts? And can I get my current carbs flowing better? These only have 5 hrs or so Thanks
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Old 04-02-2009, 08:51 PM
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Thanks guys Im going to look into headers next but wow...there damn near as much as motors.They say headers are better so I thought I would by headers even though I may not realy need them now but so as not to double buy if I ever go to bigger ci later.Any thoughts? And can I get my current carbs flowing better? These only have 5 hrs or so Thanks
Go with CMI's. THey are a good long term investment, and they will let you run more or less what you would put into that boat.

As far as carbs, I can get you custom Holleys built to spec for around $700 +-. Real nice units with billet base plates and metering blocks. 4150 flange and whichever size you want. This one is a nice 950 I have made and it cost me around $700
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Old 04-02-2009, 10:57 PM
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Just talked to Valako today. Jim is a great guy and does excellent work. I met him back in 1989 and have been friends ever since. He has a couple set of my heads right now a matter of fact. If there is power to be made somewhere Jim will find it. It may involve throwing a bolster seat or something out the boat though. ha ha.

We did talk today regarding the 496's and he feared for me knowing the way I run my boats. He has been beside me more than a few times in lake MI. I said the same thing to him that I might just wait and save for some bigger CI' engines.

Hey Rookie,
Do you recall what cam you ran in your 470's??? I think Jim and I were actually discussing your engines as I remember hearing about him doing some work for you on the board.

Let me know,
Thanks,
John
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Old 04-03-2009, 01:34 AM
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with those parts I would think your cam is TOO small. even a 731 cam should have atleast an 830 carb. I am gonna use the 741 cam with 9.5:1, edelbrock heads, edelbrock victor intake, and I think it'll need 950 or 1000 cfm carbs and make over 600 HP around 5600 RPM

Cam size really has nothing to do with carb size. Carb size is basically determined by rpm and cubic inches. You definately don't need a 950 carb on a 454-502 unless you're turning it 6500rpm. 800-850cfm is plenty.
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Old 04-03-2009, 02:29 AM
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I agree.
http://www.paulfinkmotorsports.com/Calc_3.htm

This has always been pretty close for me with the exception of blown engines.

Last edited by getrdunn; 04-03-2009 at 02:34 AM.
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