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 Post subject: another hp ?
 Post Posted: Sat Jul 03, 2010 7:46 pm 
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Joined: Sun Nov 30, 2008 8:23 am
Posts: 81
Location: Camanche IA
I have a 383 LT1 or sec gen sbc.

But if a guy went from a stock hv1002 to a ported hv1002 and went from a 280 cfm -10 brodix head to a RHS 235 cc head flowing 325 how much power do you think he will pick up?

I will need some time to finish the combo do to money but hope to get the new combo together soon. I will be running the the same cam at 268*/280* duration at .050 and .730 lift. with the same headers and 1050 carb.

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383LT1  8.957 @ 151.6 mph


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 Post subject: Re: another hp ?
 Post Posted: Sat Jul 03, 2010 7:52 pm 
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Joined: Sun Nov 30, 2008 8:23 am
Posts: 81
Location: Camanche IA
No dyno numbers but the car has ran 10.50's at 128 mph on motor with the old parts at 3200 lbs.
Not sure how head cfm is going to work to horsepower but that and the intake I hope to be worth a fair amount.

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383LT1  8.957 @ 151.6 mph


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 Post subject: Re: another hp ?
 Post Posted: Sun Jul 04, 2010 3:57 am 
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Joined: Sat Feb 07, 2009 4:12 pm
Posts: 1215
Location: Adelaide Australia
For a very rough estimate divide the HP with the old heads by the flow and multiply the answer by the new flow.
Alternatively an estimate of how much power heads will make get the CFM @28" and multiply it by .258 and then by the number of cylinders. EG 325CFM *.258*8 = 670hp. Thats a fair figure for most single carby deals. Some people use .278 instead of .258.
Next take HP estimate * 1.2 and that's the CFM passed through the engine. Figure that into RPM needed to pump that much at maybe 105%VE and you have the rev range. Then cam it to that rev range. Easy huh!. That method always gets it in the park.
From the ET and MPH its makes about 525 to 545 hp. And from the old flow figures it was around 577hp approximately so that difference can easily be soaked up in chassis setup and power delivery efficiency and a bit of tuning here and there.


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