#41  
Old 10-22-2010, 01:52 PM
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Originally Posted by Jim Robertson View Post
Both sets of my heads have divider flush with surface. I101 and C142. The I101 dated heads are in question. Flange on both heads is approximately .060" thinner than the
C142 heads. My guess is milling has occured on the I101s. How deep is the recess on an untouched head? In other words how much milling would it take to "remove" the recess?
Jim
Steve - refer to Jim's old post (#15 in this thread) quoted above.

Dunno why anyone would want to surface the intake side of these heads that much, but . . .

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  #42  
Old 10-22-2010, 02:23 PM
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I101 & I171 my pair, both have scallops.

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  #43  
Old 10-25-2010, 01:21 AM
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Why so much milling on the intake side? Could be because the heads were used on a NHRA Super Stock engine for example. Rules require a certain intake port volume...so milling the intake flange decreases the port volume allowing the enterprising engine builder to increase the volume where "needed" namely below the valve seat. With a nice big 75 degree bowl cut under the valve seats, the flow increases 25 cfm...and the power follows. :-)

  #44  
Old 10-25-2010, 01:30 PM
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Originally Posted by Jim Robertson View Post
Why so much milling on the intake side? Could be because the heads were used on a NHRA Super Stock engine for example. Rules require a certain intake port volume...so milling the intake flange decreases the port volume allowing the enterprising engine builder to increase the volume where "needed" namely below the valve seat. With a nice big 75 degree bowl cut under the valve seats, the flow increases 25 cfm...and the power follows. :-)
Dunno, Jim.

I suspect that someone didn't want the intake port scallops?

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  #45  
Old 10-25-2010, 01:37 PM
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Quote:
Originally Posted by bird72 View Post
I101 & I171 my pair, both have scallops.
Added to my list.

Thanks!

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  #46  
Old 10-25-2010, 01:44 PM
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C142 no scallops. Restored them 30 years ago. Still sittin on the shelf.
Also, mine have all 6 bolt holes on the exhaust side.

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  #47  
Old 04-06-2014, 09:25 AM
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What is the school of thought on scallops today? Run them as is, or fill with exopy, or mill them down?
Dave Clark

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  #48  
Old 04-07-2014, 02:44 PM
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What is the school of thought on scallops today? Run them as is, or fill with exopy, or mill them down?
Dave Clark
Hey Dave - here's my ".02" worth . . .

For MOST street applications you'd NEVER feel or measure the difference, leave 'em as is.

For all-out racing applications a "tuned" intake runner is more desirable, so fill (with "Devcon"?) and machine to match the existing intake interface.

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  #49  
Old 10-10-2019, 12:28 PM
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This post was referred to me about the scallops I had a question on by another member. But the heads with the scallops are dated I241 to add to your list.

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Old 10-10-2019, 04:10 PM
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How do they fair with compression test ,with that section voided of gasket sealing?

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