flow rate on 10128374 heads?
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Pro
Joined: Feb 2006
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From: powhatan va.
flow rate on 10128374 heads?
does anybody know or know where i can find out what the flow rate on a set of stock 10128374 heads is? building a engine and the buider needs to know so he can get the best cam for the heads thanks 
Drifting
Joined: Apr 1999
Posts: 1,261
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From: Middletown New Jersey
Sorry, I don't know the answer to your question but I can offer of a bit of advice. The heads are the most important factor in making power. Don't settle on heads just because you happen to have them. I made this mistake and I regret it.
Choose a set of heads that will flow enough to accomplish your power goals and then choose cam, etc...
Just my .02
Choose a set of heads that will flow enough to accomplish your power goals and then choose cam, etc...
Just my .02
Burning Brakes
Joined: Nov 2004
Posts: 781
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David, LT1 heads flow as follows:
Intake port-.100"/58 cfm
.200"/113 cfm
.300"/167 cfm
.400"/203 cfm
.500"/212 cfm
.600"/ they are probably topped out around .530" lift
Exhaust port-.100/47 cfm
.200/97 cfm
.300/133 cfm
.400/152 cfm
.500/160 cfm
.600/ they are probably topped out around .550" lift
If this is the set I mildy ported for you, then you can figure about 10 to 15 cfm increases, starting around .400" lift and working your way up to a peak around .550" lift.
I would run a cam that has moderate duration (over 220 @ .050") and lift around .540" to .560". LSA around 113 or 114, if you are keeping it a 350 c.i..
Intake port-.100"/58 cfm
.200"/113 cfm
.300"/167 cfm
.400"/203 cfm
.500"/212 cfm
.600"/ they are probably topped out around .530" lift
Exhaust port-.100/47 cfm
.200/97 cfm
.300/133 cfm
.400/152 cfm
.500/160 cfm
.600/ they are probably topped out around .550" lift
If this is the set I mildy ported for you, then you can figure about 10 to 15 cfm increases, starting around .400" lift and working your way up to a peak around .550" lift.
I would run a cam that has moderate duration (over 220 @ .050") and lift around .540" to .560". LSA around 113 or 114, if you are keeping it a 350 c.i..
Burning Brakes
Joined: Nov 2004
Posts: 781
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I would guess that the head's flow is starting to level off around .530" to .540" (no longer increasing the cfm), and beyond .550" would begin to go 'backwards' (decreasing cfm). I believe anywhere between .525" and .550" your flow numbers are going to be about the same, but a little bit of extra lift will increase the amount of time the valve is open while the head is moving the greatest amount of air. .540" lift is a pretty good choice for getting the most out of a mild/stock LT1 head, yet not requiring lots of duration to increase power over a stock cam.
