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head question

1K views 8 replies 6 participants last post by  L6571SS 
#1 ·
I"m in the process of rebuilding my 350, and was wondering what heads to use. I have a 4 bolt, bored 30 over, polished pink rods, trw forged pistons 10.1 with 64cc heads, stock crank, comp extreme cam .487/.490 lift, performer RPM intake, 650 holly double pumper. I'm looking to get between 350 to420 hp. I was thinking of going with the vortec heads, and was wondering if that will get the hp i want. MY original plan was to go with performer rpm aluminum heads, but really don't want to spend the money if i can get 350hp from the vortec heads. Just wondering what some people think of this combo, and what hp this setup might put out.


Thanks,
lucky3


[This message has been edited by lucky3 (edited 10-16-99).]
 
#4 ·
Where are you gonna get gas for your 10:1 motor? I think it's just outside of comfortable unless
#1)you run the aluminum heads-they will soak up more heat and allow up to 10.5:1 on pump gas.
#2)that cam has lots of overlap, lessening your combustion pressure. You might also play with cam timing for the same effect.
or
#3)you don't mind running octane booster ALL the time.
Detonation is no fun. I'd either run the aluminum heads at 10:1 (my 1st choice), or find a set of 76cc heads and recam for a 9:1 motor. Good luck, Bryan
Oh yeah, you'll probably be happier with a 750dbl pmpr too-- if you want to get power from your motor, you GOTTA let it breathe.


[This message has been edited by Bryan (edited 10-17-99).]
 
G
#5 ·
Lucky3, carbs don't make a motor breathe, the heads, cam and the intake manifold do the breathing. GM put 585 cfm vacuum carbs on the 327/365 motor and 427/390 motors, I think the 650 is about right although I not a big fan of the double pumper on street cars.

The compression is not excessive, the cam you have will help bleed cylinder pressure.

I don't know the casting number of your iron heads, if you could post that it might be helpful.


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Wally
Gold #67
67 Malibu "Small Block"
90 SS454
71 Malibu "Small Block"
93 torch red vette
 
#8 ·
For about the same money as the vortecs (new intake, valve covers, rockers) you could put on World SR Torquers. They are excellent with thicker surfaces, screw in studs, 2.02"/1.60" stainless valves, and springs good to .510"+. These heads will make up to around 410hp. With just a little short side radius work, they will flow even better. Put the 76cc version with a steel shim gasket (for a tight quench) for 9:1 or the 67cc version w/steel shim for 9.75:1 CR.

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Pat Kelley
66 El Camino, daily driver
67 El Camino, STRIP/street
 
#9 ·
With Vortecs you can run the 10:1 with pump gas easy. I have a friend running it on mid grade with no problems(with vortec heads). Some problems you would have with the vortecs is that you can't use the the intake for a standard small block and you need self alighning rockers. Also the stock springs will not handle your cam and they have pressed in studs. Bang for the buck vortecs are very good. They flow 239 on the intake side compared to S/R Torquers 205. The S/R are a good stock type replacement so you can use the stock type intake and rockers.

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JT
71 SS Vortec 355
www.angelfire.com/co/KellyMotorsports
 
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