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05-29-2015, 01:52 PM
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#1 |
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Registered User
Join Date: May 2003
Location: Ontario
Posts: 279
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HP/Torque estimate
Engine is at machine shop waiting to be done,I am unanxiously waiting to get it back.With my combo how much power will it make
.030 over 427 10.2-1 pistons cam is solid roller 252/257 with a .652 lift I/e Dart Pro 1 heads 310 cc,roller rockers w/stud girdle 121 cc chamber 2.25 I 1.88 ex Edelbrock Vic Jr intake Holley 850 df dp 2 inch Hooker headers Thanks |
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05-29-2015, 02:29 PM
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#2 |
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Registered Truck Offender
Join Date: May 2008
Location: hells training ground (aka Ariz)
Posts: 3,118
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Re: HP/Torque estimate
A whole lot of little things add up,, like is the 10.2 a measured compression given your deck clearance gasket and CH,, or just the advertised from the piston manufacturer.
Wasthe bores finished with a torque plate,, and proper finish for the rings (plasma moly ?) file- fit to minimize gap. Vacuum pump or just breathers... I've seen pump gas 427's go well north of 555HP,, and I've seen them struggle to make 450. Attention to detail can make that much difference.
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Still playin with trucks, even at my age! When you're dead, it's only a problem for the people around you, because you don't know you're dead. .....It's kinda the same when your STUPID. I just did my taxes and reviewed my SS statement. Thanks to the current administration it looks like I will only have to work till noon on the day of my funeral. |
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05-29-2015, 02:34 PM
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#3 | ||||
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"I ain't nobody, dork."
Join Date: Sep 2007
Location: Whidbey Island, Washington
Posts: 8,921
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Re: HP/Torque estimate
425+
 Gary
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'cuz chicks dig scars... My 1972 GMC 1500 Super Custom (Creeping Death) "long term" build thread. The Rebuild of Creeping Death after the wreck Quote:
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05-29-2015, 05:07 PM
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#4 |
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Registered User
Join Date: May 2003
Location: Ontario
Posts: 279
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Re: HP/Torque estimate
bores were finished with torque,plates,moly rings,10.2 is measured compression with gasket,my last engine had stock 241 casting heads with 2.225/1/88 valves,gasket matched,113 cc heads,had a 246/252 cam with .590/.598 lift solid tappet cam11.5 -1 closed chamber pistons with open chamber heads dual plane and 750 carb,and ran a 12.10 @110 in a 4000 lb truck that figures to about 450 ish,with the larger roller cam and better flowing heads ,single plane and 850 was hoping for 550-600
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05-30-2015, 10:34 AM
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#5 |
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Registered Truck Offender
Join Date: May 2008
Location: hells training ground (aka Ariz)
Posts: 3,118
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Re: HP/Torque estimate
Do you have a flow sheet for the heads?
With 11.5 compression and iron heads in the old setup you were obviously not running pump 87..... what fuel are you planning to run now? My opinion (and I'm no big block guy so take this with a grain of salt... may not even be worth that) But at only 10.2:1 compression you are MAXED out on duration. The old engine builders 'rule of thumb' of 250° @ 0.050" for 10:1.... 260 for 11:1 etc was a MINIMUM compression to support the duration. I would love to see this motor on an engine dyno to see where the torque and peak HP. I bet you have to spin it pretty hard to get the most out of that cam at this compression. but again just a smallblock guys ramblings.. a big block head responds so totally different
__________________
Still playin with trucks, even at my age! When you're dead, it's only a problem for the people around you, because you don't know you're dead. .....It's kinda the same when your STUPID. I just did my taxes and reviewed my SS statement. Thanks to the current administration it looks like I will only have to work till noon on the day of my funeral. |
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05-31-2015, 09:17 PM
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#6 |
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Registered User
Join Date: May 2003
Location: Ontario
Posts: 279
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Re: HP/Torque estimate
11.5-1 closed chamber pistons with open chamber heads was good for about 10.75 -1 ,I used 4 gallons of 94 with 1 gallon of leaded 110 just because I didn't have hardened seats,the heads are Dart Pro 1 310 cc BNIB so the Dart website should have a flow chart for them.I have a 4.86 gear will spin it to 7000
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05-31-2015, 09:39 PM
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#7 |
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Registered User
Join Date: Oct 2003
Location: Carmichael, California
Posts: 3,006
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Re: HP/Torque estimate
[QUOTE=Marv D;7191448 The old engine builders 'rule of thumb' of 250° @ 0.050" for 10:1.... 260 for 11:1 etc was a MINIMUM compression to support the duration. [/QUOTE]
That use to be the old school way but with modern cam profiles and more custom ground cams being used its not a factor anymore. Compression makes more power but not something to base your camshaft on. The valve timing events can be changed so that a 9:1 engine will make more cylinder pressure than a 10:1 engine. Besides, the camshaft doesnt know what compression the engine has. I would guess this engine to be in the 525hp range. Did you have the heads flowed? I think those Dart heads are going to want more split on the exhaust valve.
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