GM and AFR CNC head pictures
02-11-2005, 06:11 PM
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GM and AFR CNC head pictures They're not really useful, but I thought you guys might like to see a few pictures of the GM CNC LS6 and AFR heads side by side. I got the GM heads from a friend for cheap, and I had planned to install them, but then read too many posts from Tony M and decided to go with the AFRs instead. Got the AFRs from SDPC today. Now if I can just decide between the GT2-3 or AFR 220/224 cam, I'll be ready to put the damn car back together!
The AFRs are at least 25% heavier, maybe more.
GM on left, AFR on right
AFR intake port
GM intake port
GM intake port
AFR exhaust port
GM Exhaust port
GM chambers 60cc
AFR chambers milled to 62cc
The AFRs are at least 25% heavier, maybe more.
GM on left, AFR on right
AFR intake port
GM intake port
GM intake port
AFR exhaust port
GM Exhaust port
GM chambers 60cc
AFR chambers milled to 62cc
Last edited by Flareside; 02-11-2005 at 06:45 PM.
02-11-2005, 06:27 PM
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Hi
Great pictures - they are very interesting. The one thing that I noticed is the ARF chambers is a lot smoother than the GM but other then that, they look very much the same. The real test work to take a stock LS1 and try each head on the motor to see which one made the most power. I bet it would very close. Just my two cents
Bill
Great pictures - they are very interesting. The one thing that I noticed is the ARF chambers is a lot smoother than the GM but other then that, they look very much the same. The real test work to take a stock LS1 and try each head on the motor to see which one made the most power. I bet it would very close. Just my two cents
Bill
. those are the GMMP LS6 heads right?
02-11-2005, 06:42 PM
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Originally Posted by 70T/A400
In your opinion, what are the physical differences between the heads? Thanks,
Glen
Glen
The GM heads are actually the GMPP LS6 CNC heads, part number 88958622.
The chamber shapes surprised me, I didn't think there would be so much difference. I wonder what the technical reason for the change from a heart shape to a figure 8 is? The bump at the plug is also completely different.
Last edited by Flareside; 02-11-2005 at 06:50 PM.
02-11-2005, 06:54 PM
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Originally Posted by Bill's 02 Z-28 SS
Hi
Great pictures - they are very interesting. The one thing that I noticed is the ARF chambers is a lot smoother than the GM but other then that, they look very much the same. The real test work to take a stock LS1 and try each head on the motor to see which one made the most power. I bet it would very close. Just my two cents
Bill
Great pictures - they are very interesting. The one thing that I noticed is the ARF chambers is a lot smoother than the GM but other then that, they look very much the same. The real test work to take a stock LS1 and try each head on the motor to see which one made the most power. I bet it would very close. Just my two cents
Bill
02-11-2005, 06:59 PM
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Originally Posted by Flareside
The flow number make me believe that dyno numbers would be similar, but I'm really hoping that the smaller AFR port provides better throttle response that the dyno would never detect. We'll see. I measured an intake port in each head, the AFR was 206cc, the GM was 241. Big difference.
Good luck!
Ed
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02-11-2005, 07:11 PM
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Originally Posted by Flareside
Visually, they look very similar, but when you lift them you can really feel a difference. The AFRs are at least 25% heavier/thicker. I'll try to weigh them later tonight.
The GM heads are actually the GMPP LS6 CNC heads, part number 88958622.
The chamber shapes surprised me, I didn't think there would be so much difference. I wonder what the technical reason for the change from a heart shape to a figure 8 is? The bump at the plug is also completely different.
The GM heads are actually the GMPP LS6 CNC heads, part number 88958622.
The chamber shapes surprised me, I didn't think there would be so much difference. I wonder what the technical reason for the change from a heart shape to a figure 8 is? The bump at the plug is also completely different.
02-11-2005, 09:59 PM
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Originally Posted by Ragtop 99
Is it the angle of the photos or did AFR raise the floor of the intake port?
I'll try to get a better set of pictures of the intake ports.
02-11-2005, 10:12 PM
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Originally Posted by Flareside
That's no camera angle, that's why I spent $2200!
I'll try to get a better set of pictures of the intake ports.
I'll try to get a better set of pictures of the intake ports.
GM CNC: 22.8 lb
AFR: 27.8 lb
LS1: 24 lb
GM
AFR
GM
AFR
The AFR intake ports are way smaller than the CNC LS6 ports. You can hardly even see the valves in the AFR ports.
02-11-2005, 10:30 PM
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Some people call the shape a peanut shaped combustion chamber- it is a better design because of the dual quench that it has to direct the air/fuel mixture into the center of the cylinder for a more effiecient burn, like a fast burn head.
02-13-2005, 07:59 AM
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Excellent pics. very helpful and useful!
My observations are GM port has floor carved out heavily, and since its milled on deck heavily that is reason it appears AFR is much taller. Prolly not much difference as cast. Taller shortside shows more efficient design of AFR.
Dual quench design of chamber helps to seperate exhaust and intake gasses during overlap and this speeds up burn time. Thanks for great pics!
Does Afr intake valve appear canted to anyone else? It sure does to me.
My observations are GM port has floor carved out heavily, and since its milled on deck heavily that is reason it appears AFR is much taller. Prolly not much difference as cast. Taller shortside shows more efficient design of AFR.
Dual quench design of chamber helps to seperate exhaust and intake gasses during overlap and this speeds up burn time. Thanks for great pics!
Does Afr intake valve appear canted to anyone else? It sure does to me.
