LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

intake not matching to heads

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Old May 19, 2009 | 01:13 PM
  #1  
95Blackhawk's Avatar
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From: Phoenix, AZ
intake not matching to heads

OK, Not a big deal and the car runs fine. Checked it with a mirror and light on each intake port.

I just wanted an idea of what I might be doing to my HP numbers knowing that the head is about 1/16" smaller on the bottom and 1/32" on the top. Vertical sides seem to matched up very well.

From a basic standpoint, I know it shouldn't really impact my running. However, I know the theory is to have smooth flow through the port and a disturbance will impact that flow and thus speed of the charge.

Since I intend to push the car to 6700 RPM this coming race season, I am wondering if it is worth it to get the heads cleaned up since they are out. I regularly keep the car in the 4-6K range when racing so the upper end is where I am concerned.

I just don't want to shell out money for additional port work (it has been done before) if the HP will not matter (less than 20 lets say).

Thanks,
Ben
Old May 19, 2009 | 01:19 PM
  #2  
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Originally Posted by 95Blackhawk
OK, Not a big deal and the car runs fine. Checked it with a mirror and light on each intake port.

I just wanted an idea of what I might be doing to my HP numbers knowing that the head is about 1/16" smaller on the bottom and 1/32" on the top. Vertical sides seem to matched up very well.

From a basic standpoint, I know it shouldn't really impact my running. However, I know the theory is to have smooth flow through the port and a disturbance will impact that flow and thus speed of the charge.

Since I intend to push the car to 6700 RPM this coming race season, I am wondering if it is worth it to get the heads cleaned up since they are out. I regularly keep the car in the 4-6K range when racing so the upper end is where I am concerned.

I just don't want to shell out money for additional port work (it has been done before) if the HP will not matter (less than 20 lets say).

Thanks,
Ben

So, to paraphrase, the ports in the heads are smaller than the gasket and the intake manifold...is that right? I'm really surprised that ported heads aren't already gasket matched.

Whether the ports in the heads or the manifold are smaller doesn't really matter...you can gasket match either yourself to improve flow. However, the tiny difference you're talking about probably won't net you 20 ponies

:THUMB:
Old May 19, 2009 | 02:45 PM
  #3  
95Blackhawk's Avatar
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Originally Posted by bw_hunter
So, to paraphrase, the ports in the heads are smaller than the gasket and the intake manifold...is that right? I'm really surprised that ported heads aren't already gasket matched.
You are correct on smaller head ports.

I am surprised also on the matching but what is most interesting is the intake (essentially untouched) is larger than the gasket itself. Kinda wierd.

I have a dremel so could do "something" but without a junk head to practice on, not sure if I want to get too aggressive.
Old May 19, 2009 | 08:16 PM
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look like these?


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https://www.camaroz28.com/forums/sho...d.php?t=680229
https://www.camaroz28.com/forums/sho...d.php?t=681965

Iv cleaned the ports up since but no new pictures
Old May 20, 2009 | 02:55 PM
  #5  
95Blackhawk's Avatar
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Originally Posted by slowride94z
Yes. The vertical match is just fine it is my lower and upper horizontal that do not match.

How did you clean them up? I am thinking of buying a porting kit from Summit for $30 and doing some very cautious grinding. Intent is not to change the design of the port but to smooth out that transition.

Ben
Old May 20, 2009 | 07:26 PM
  #6  
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From: Bennett N.C.
Originally Posted by 95Blackhawk
Yes. The vertical match is just fine it is my lower and upper horizontal that do not match.

How did you clean them up? I am thinking of buying a porting kit from Summit for $30 and doing some very cautious grinding. Intent is not to change the design of the port but to smooth out that transition.

Ben
https://www.camaroz28.com/forums/sho...d.php?t=681965

check out this post. I did what they said and moved my burr quicker and side to side on a 45* angle then some home made cartridge rolls

for just port matching like your talking about just use the kit your talking about and scribe the port with an awl using an intake gasket, a burr takes off aluminium too quickly sometimes . blend it back about an inch

Ill go take some pictures
Old May 20, 2009 | 08:03 PM
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Name:  049.jpg
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I had trouble following the lines with the burr
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