Iron head question
#660871
04/04/10 07:50 PM
04/04/10 07:50 PM
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Joined: Mar 2003
Posts: 1,710
Spokane Wa
CrazyRocker70
OP
top fuel
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OP
top fuel
Joined: Mar 2003
Posts: 1,710
Spokane Wa
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looking at some of fast68plymouths articles on the tech board, i was wondering if i could support 500 horse with the heads i have. links i used for comparison: http://www.moparts.org/Tech/Archive/bb/4.html http://www.moparts.org/Tech/Archive/bb/40.htmlmy heads: 906 castings, .060 milled off. 2.14/1.81 stainless valves w/ back cut. 3 angel valve job with bowl porting. from fasts article, and the work done to the heads i have i would assume they are in the 250cfm range @ .550 lift aluminum is a bit pricey, and these are already done. just wondering if i can get what i want out of them thanks for any help!
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Re: 383man
[Re: 383man]
#660876
04/04/10 09:26 PM
04/04/10 09:26 PM
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Joined: Mar 2003
Posts: 1,710
Spokane Wa
CrazyRocker70
OP
top fuel
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OP
top fuel
Joined: Mar 2003
Posts: 1,710
Spokane Wa
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thanks ron, i remember talking to you awhile back about that 557 stick and your combo. thats why i was looking at flow around .550 what i have planned: steel crank, stock rods, pistons in the 10:1 range (have to cc the combustion chamber still), the 906's from above, holley sd, 850 speed demon (got a screamn deal on it) 1" open spacer if it will fit, mp elec dist, and either the dough throleys 1 3/4 header or the tti 1 7/8 the car is a 71 runner, 727 3.55's lookn to buid a street car with nuts, it will get a little strip time but not much... dont have the budget for it 
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Re: 383man
[Re: CrazyRocker70]
#660878
04/04/10 09:40 PM
04/04/10 09:40 PM
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Joined: Aug 2003
Posts: 43,159
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,159
Bend,OR USA
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I have made a bunch(ten or more) of stock stroke pump gas 440 motors that made 500+ HP with more torque than HP. None of them where what I would consider a "quench" motor, all of them had flat top pistons, some with valve reliefs some not. Most of the iron heads had the same size valves as yours but some where stock size with mild porting, the best heads flowed 266 @ .500 on a Super flow 600 bench using 28 inches of water on the intake side. The cams varied from a Comp Cams XE28HL to a solid lifter Reed cam(the most HP ,535 HPat 5900 RPM,and Tque 560 FT lbs at 4200 RPM  )that was ground on a 101 LSA  Take a good hard look at Comps XE-HL sereis hydraulic cams  Most of those motors had either a Eddey Performer RPM intake or a Mopar single plane 4150 with at least a 800 CFM Holley or BG double pumper, three had the Holley 950HP. Your set up and car combination would make me want to use the Comp Cams XE284HL with a set of 1.6 rockers and a good 3000 RPM converter (11 inch ) 
Last edited by Cab_Burge; 04/04/10 09:43 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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383man
[Re: CrazyRocker70]
#660880
04/05/10 12:13 AM
04/05/10 12:13 AM
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Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
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Quote:
thanks ron, i remember talking to you awhile back about that 557 stick and your combo. thats why i was looking at flow around .550
what i have planned: steel crank, stock rods, pistons in the 10:1 range (have to cc the combustion chamber still), the 906's from above, holley sd, 850 speed demon (got a screamn deal on it) 1" open spacer if it will fit, mp elec dist, and either the dough throleys 1 3/4 header or the tti 1 7/8
the car is a 71 runner, 727 3.55's lookn to buid a street car with nuts, it will get a little strip time but not much... dont have the budget for it
That is real close to my 440 as I use the Street Dominator intake with an 850 DP. I also use Hedman 1-3/4 headers with 3" exh. I use 4.30's but with a 30" tall tire. I drive it 55 to 60 mph all the time taching in the 3000 to 3400 rpm range. In fact I drove it almost 100 miles today (45 miles one way) on a 55 mph road to see my mom and dad. It was just to nice a day here in Md not to drive my 63.  But it sounds like you will have a nice running car in the 500 hp area. Ron
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Re: 383man
[Re: CrazyRocker70]
#660881
04/05/10 12:29 AM
04/05/10 12:29 AM
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Joined: Dec 2003
Posts: 5,314
Carstairs, Alberta, Canada
dave571
master
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master
Joined: Dec 2003
Posts: 5,314
Carstairs, Alberta, Canada
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Quote:
thanks ron, i remember talking to you awhile back about that 557 stick and your combo. thats why i was looking at flow around .550
what i have planned: steel crank, stock rods, pistons in the 10:1 range (have to cc the combustion chamber still), the 906's from above, holley sd, 850 speed demon (got a screamn deal on it) 1" open spacer if it will fit, mp elec dist, and either the dough throleys 1 3/4 header or the tti 1 7/8
the car is a 71 runner, 727 3.55's lookn to buid a street car with nuts, it will get a little strip time but not much... dont have the budget for it
I think you are on track with your build but the 850 speed demon is the wrong carb, no matter how good of a deal you got on it.
Main reason is, that carb is for cams with less than 240 @ 50 duration. ( I think you'll be over 240 to get the 500 horses you want)
It will not tune properly with that much cam. I run a similiar build myself, and use a 750 Mighty demon. It is made for cams with duration of 240 - 260.
You could run an 850 mighty, or a 750 mighty, and either would likely work, but a speed demon is the wrong carb for you. Keep in mind, a 750 demon does NOT flow the same as an 750 it holley. It flows closer to 830 cfm. I replaced my 750 with a 950 hp holley, and saw no performance gain or loss.
Sell the speed demon,a nd put the money into a mighty demon
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Re: 383man
[Re: joedust451]
#660883
04/05/10 09:22 PM
04/05/10 09:22 PM
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Joined: Mar 2003
Posts: 1,710
Spokane Wa
CrazyRocker70
OP
top fuel
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OP
top fuel
Joined: Mar 2003
Posts: 1,710
Spokane Wa
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wow, thought i lucked out with that carb too  guess its time to go mighty.. any one know where i can find more specifics on holley/ demon carbs? ive heard that the 850 holley dp will flow in the 900 range, the 750 demon in the 830 range.. is there somewhere i could reference information like this?
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