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317 heads power potential?

Old 01-22-2017, 04:48 PM
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Default 317 heads power potential?

Trying to plan out my 6.0 build and I'm wondering what the power potential of the stock 317 heads in naturally aspirated form if I have them CNC ported. My plans are using the stock crank with Eagle rods and Mahle pistons and shooting for 11.5:1 compression. Nitrous is a possibility too.

thanks!

Dan

Last edited by Dan.Chevelle; 01-22-2017 at 08:36 PM.
Old 01-22-2017, 08:39 PM
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Should flow the same as ported 243/799's. AI offers the same cnc program for all 3 castings. 317's have a larger combustion chamber however. I'm getting ready to bolt on a set of 317's that AI welded the chamber on to get to 62cc.
Old 01-22-2017, 08:42 PM
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Originally Posted by z-camaro
Should flow the same as ported 243/799's. AI offers the same cnc program for all 3 castings. 317's have a larger combustion chamber however. I'm getting ready to bolt on a set of 317's that AI welded the chamber on to get to 62cc.
What is the rest of your combination and horsepower goals?
Old 01-22-2017, 08:45 PM
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Here is my build thread, I am hoping for 440/415. https://ls1tech.com/forums/generatio...-eps-mamo.html
Old 01-22-2017, 08:50 PM
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Originally Posted by z-camaro
Here is my build thread, I am hoping for 440/415. https://ls1tech.com/forums/generatio...-eps-mamo.html
Thank you. Where is AI, the machine shop you recommend? I was thinking of sending mine to Texas Speed and having them match the cam.
Old 01-22-2017, 09:01 PM
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Originally Posted by Dan.Chevelle
Thank you. Where is AI, the machine shop you recommend? I was thinking of sending mine to Texas Speed and having them match the cam.
Found it, Advanced Induction. Looks like a solid build and the numbers I am looking for.
Old 01-22-2017, 09:24 PM
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FWIW

As I understand, In theory a properly ported 317 or 243/799 head can flow about 325 to 330 cfm which is in theory enough to support about 725 hp NA at the flywheel. However, most of the popular intake manifolds don't allow for that full air flow and reduce it by 20 to 60 cfm.

I seem to recall seeing online a few cars with 243/799's making about 550 at wheels.

I've read that the Wegner NASCAR spec engine with Wegner ported 243/799 heads made about 585 to 595 wheel hp which seems reasonable spining to 8,000 -8,200 rpm in a prepared race car/truck.
Old 01-23-2017, 07:27 AM
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Originally Posted by 99 Black Bird T/A
FWIW

As I understand, In theory a properly ported 317 or 243/799 head can flow about 325 to 330 cfm which is in theory enough to support about 725 hp NA at the flywheel. However, most of the popular intake manifolds don't allow for that full air flow and reduce it by 20 to 60 cfm.

I seem to recall seeing online a few cars with 243/799's making about 550 at wheels.

I've read that the Wegner NASCAR spec engine with Wegner ported 243/799 heads made about 585 to 595 wheel hp which seems reasonable spining to 8,000 -8,200 rpm in a prepared race car/truck.
Thank you. Just trying to see if it is worth it to spend the extra money for ported LS3 heads or if the 317 cathedral ports are good enough.
Old 01-23-2017, 09:00 AM
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Default LS-7 Camshaft with a Hendrick Head

Hi, you may have other concerns BEFORE you would install a Hendrick head.

First, I like a High Swirl port good for combustion quality.
This head is better for low speed, under 5000 RPM, engine performance.
There will be a higher BSFC with the 317 head in lower speed running, good for lower fuel consumption.

The camshaft LSA would be a DIFFERENT choice for each head.
A Hendrick head choice could use MORE Intake Valve Lift due to the fitment of the larger valve.

What is your cam LSA ?

Lance
Old 01-23-2017, 10:49 AM
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Originally Posted by Pantera EFI
Hi, you may have other concerns BEFORE you would install a Hendrick head.

First, I like a High Swirl port good for combustion quality.
This head is better for low speed, under 5000 RPM, engine performance.
There will be a higher BSFC with the 317 head in lower speed running, good for lower fuel consumption.

The camshaft LSA would be a DIFFERENT choice for each head.
A Hendrick head choice could use MORE Intake Valve Lift due to the fitment of the larger valve.

What is your cam LSA ?

Lance
I actually haven't picked a cam yet, it was my plan to decide on heads first and choose the cam depending on the heads I choose. If I can make between 450-500 rwhp with ported 317s I'll probably stick with those.
Old 01-23-2017, 02:46 PM
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Dan Chevelle, your welcome.

Stock LS3 heads can flow around 320 cfm peak and good mid flow as well. Ported they can flow 365+ cfm. They do have more potential.

My 91 RS Camaro LS1 383 made 465 rear wheel hp with an older (2003-2004) set of TEA Stage 2.5 LS6 heads. Many people have made 450+ with ported LS6 type heads.
Old 01-23-2017, 11:34 PM
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Originally Posted by 99 Black Bird T/A
Dan Chevelle, your welcome.

Stock LS3 heads can flow around 320 cfm peak and good mid flow as well. Ported they can flow 365+ cfm. They do have more potential.

My 91 RS Camaro LS1 383 made 465 rear wheel hp with an older (2003-2004) set of TEA Stage 2.5 LS6 heads. Many people have made 450+ with ported LS6 type heads.
Thanks for the input. I spoke to Texas Speed today and they recommended a set of LS6 heads over 317s for better compression. My thoughts at thispoint are unless I can find some LS6, 248 castings I believe for dirt cheap and have them ported I would probably be better off to spend the money on ported LS3 heads.


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