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disgusted
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210 Posts
Discussion Starter #1
So I came over a 99 lq4 with iron heads, and I know that 243s or 799s are basically the best as far as flow from the factory, the valves being the advantage in the 243s. My question is, what other heads are good with a port/polish? I mean I'd love 243s but I'm trying to build this motor on somewhat of a budget and $500 for a set of heads is just a little steep. What other casting numbers can produce good flow with a nice port/polish, stronger springs and maybe valves?
 

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QuadraSteernado
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8,385 Posts
317s flow practically the same as 243/799s. They just have a larger CC to them.

L92 heads are the new animals but you will need a matching intake
 

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ΜΟΛΩΝ ΛΑΒΕ
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8,527 Posts
317s flow practically the same as 243/799s. They just have a larger CC to them.
This, they just yield a lower comp ratio than the 243/799s.

Also the stock iron heads flow just as good as 317s IIRC, but are...iron.

But depending on what you are putting it in, you have bigger issues than the heads, such as the crank being too long on the 99-00 LQ4s meaning you cannot bolt it to the 4l60e in place of your 4.8/5.3.
 

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disgusted
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210 Posts
Discussion Starter #4
This, they just yield a lower comp ratio than the 243/799s.

Also the stock iron heads flow just as good as 317s IIRC, but are...iron.

But depending on what you are putting it in, you have bigger issues than the heads, such as the crank being too long on the 99-00 LQ4s meaning you cannot bolt it to the 4l60e in place of your 4.8/5.3.
This I am already aware of. I scored on a LS1 crank with about 9k on it from a friend when they opted to boost the car rebuilding it from the bottom up. I want to send it to the shop all at the same time so I want to figure out what I'm doing with the heads first. I just don't want to do it twice. If it'd be more cost effective to just P&P what I have and roll with it, sweet. Just looking for opinions from people who have tried a couple different combos.
 

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Registered
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603 Posts
i personally wouldnt use that early Lq4 for anything other then the block itself. the rods are extremely weak in that year motor for any kind of power
 
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