What's better, compression or headflow ?
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Teching In
Joined: Dec 2005
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What's better, compression or headflow ? I have a 2000 Camaro LS1 motor with stock 853 cylinder heads on it now. I am running the 02-04 LS6 camshaft (.551 lift).
I also have an extra set of LQ4 317 heads available and I was wondering what would make more power?
If I leave the 853"s on I will keep my 10:1 comp ratio. But if I swap to the 317"s I will lose the compression down to around 9.5:1, but gain cyl. head flow as the heads flow the same as the ls6 heads.
There are no immediate plans to boost this engine anytime soon.
Has anyone done this head swap?
How much power do you think I would gain/loose?
Thanks in advance.
I also have an extra set of LQ4 317 heads available and I was wondering what would make more power?
If I leave the 853"s on I will keep my 10:1 comp ratio. But if I swap to the 317"s I will lose the compression down to around 9.5:1, but gain cyl. head flow as the heads flow the same as the ls6 heads.
There are no immediate plans to boost this engine anytime soon.
Has anyone done this head swap?
How much power do you think I would gain/loose?
Thanks in advance.
Can't you just mill those 317's to increase the compression? Then have the same cr and better flow.
But either way....I think the rule of thumb is like 4% increase in power for every point increase in compression. So, if thats true, you're looking at a 2% loss by going down to 9.5:1 cr. So 350 RWHP will drop to about 343 RWHP.
But rule of thumb on HP increase with better flowing heads could be 1.5 HP per cfm increase.
So, if those 317's will flow just 15 cfm better than the 815's.....you'll increase power by 22-23 RWHP. So...how much more do they flow than the 815's???
Or something like that.................if they flow alot more cfm's....do the heads. Mill them if possible and have both.
.
But either way....I think the rule of thumb is like 4% increase in power for every point increase in compression. So, if thats true, you're looking at a 2% loss by going down to 9.5:1 cr. So 350 RWHP will drop to about 343 RWHP.
But rule of thumb on HP increase with better flowing heads could be 1.5 HP per cfm increase.
So, if those 317's will flow just 15 cfm better than the 815's.....you'll increase power by 22-23 RWHP. So...how much more do they flow than the 815's???
Or something like that.................if they flow alot more cfm's....do the heads. Mill them if possible and have both.
.
Why not do the best of both worlds and shop around for some inexpensive 243 heads? Otherwise, you could try to see if you gain a little by getting the better flowing heads on there, but you might wait it out.
Since the car is a 2000, you could gain a bit more by throwing the LS6 intake on at the same time as either of those heads - provided you haven't already done so.
Since the car is a 2000, you could gain a bit more by throwing the LS6 intake on at the same time as either of those heads - provided you haven't already done so.
