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HOT AIR BALLOON OWNER
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Discussion Starter #1
I had an idea come to me here. :hmm:

How difficult would it be to run a 1.89" intake valve on the 317 cast head (sand or SPM)? It's about 0.11" smaller than the stock at 2". Exhaust would remain the same at 1.55" The 317 flows quite well stock and can pick up about 70cfm intake/40cfm exhaust with mild work on stock valves from what I've seen.

Looking at a high velocity, high torque head on the cheap maybe. If it requires new valve seats I don't think it'd be worth doing it. Maybe a 1.94" intake would work?
 

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Mayhem, Like Me
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I think you're on to something here...
 

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HOT AIR BALLOON OWNER
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Discussion Starter #3
Bump on this, anyone paid to have heads rebuilt with new valve seats?

My mind is workin back on this again. :imo
 

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heavy on the skinny pedal
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I don't see it being done without going to a new seat. and 8 seats valves and machine work I'm guessing wouldn't be the cheapest.
 

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Hope your gonna mill the shit out of them!!!!! A 71cc chamber isnt exactlly small.
This is true. You might gain flow but with that much loss in compression it definitely wouldnt be worth it unless you did mill them to death. Why not use 243 heads with the same concept? Intake valve smaller than 2" and the exhaust around 1.6". Only downside to both is that you would have to make sure they are milled and even then they are both designed for what a 3.95" bore or something like that. It will definitely take some work but I like where you are going with this
 

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HOT AIR BALLOON OWNER
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Discussion Starter #8
No, I need the large chamber to drop compression.
 

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STS turbo if its what im thinking about:imo
Well I've talked with Eric before about him fabbing up his own STS-like turbo system. It wouldnt take much. Plus he could fab up his own catch can so he wouldnt have to worry about all the STS systems oiling issues :rofl2:

If this is for FI then I like the 6.0 heads better than the 243s because you have a bigger intake runner. More room to shove as MUCH air as you possibly can into that combustion chamber
 

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HOT AIR BALLOON OWNER
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Discussion Starter #12
Yup, that's the idea. 6.0 heads are basically large chamber LS6 cast, I can't see installing and cutting new valve seats being very expensive for eight valves only. :imo
 

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HOT AIR BALLOON OWNER
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Discussion Starter #15
All the shit he talked on STS......... And look what he does!


Where? When? :gayfight:



LQ4 heads, LS6, LS2, LS1, all have 2" intake valve.
 

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keep in mind that the gain you see in flow is largely due to the bigger intake valve, put the smaller valve in it, and it cant flow as much as the bigger valve. so you've sucessfully just shot yourself in the foot. the only plus will be the bigger combustion chamber.
 

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HOT AIR BALLOON OWNER
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Discussion Starter #17
keep in mind that the gain you see in flow is largely due to the bigger intake valve, put the smaller valve in it, and it cant flow as much as the bigger valve. so you've sucessfully just shot yourself in the foot. the only plus will be the bigger combustion chamber.

Exhaust port is far better on them too. Think LT4...
 

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HOT AIR BALLOON OWNER
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Discussion Starter #19

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IMHO it wouldn't be worth the time money or trouble. All that NA stuff you can though out the window wiht FI. You now have a very good way to control flow and cylinder filling with the turbo that you didn't have with NA. Stock 317 heads work very well on boosted motor just the way they are. You want the 10hp you MIGHT see from some smaller valve, bump the boost half a pound (or less). :)
 
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