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427SC
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Discussion Starter #1
I have a 427 side oiler with heads that have a C6AE-F casting code. I have seen some info that these heads have 2.195" intake and 1.733" exhaust valves and that the valve spacing is wider on these bigger valve heads. My question is, "What is the spacing for the smaller and the larger valve heads?" The heads are currently on the engine so I can't measure the valve diameter. I'm trying to verify if these are the heads I think they are. Any help is appreciated.
 

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Std valve spacing is 2.00". Med, high riser and tunnelport is 2.10" where each valve was moved out .050. Are you sure your heads are not C5AE-F's? Those are the Medium riser castings. Some can look like a 6 but indeed are 5's. Casting numbers are often slurred together. Also there are 2 versions of those F heads. Big F and small F. There are also C6AE-R heads where the R can look like a F. Those are your standard bread and butter FE heads. Also the last version of the lowriser head as we know it. If you just can't see the casting number that well you can just measure the valve spacing center to center. Remove the valve cover and measure the valves center to center. You should be able to see and measure the difference easily. So...
C5AE-6090-F heads are 427 medium riser heads with 2.10 spacing
C6AE-6090-R heads are std FE heads with 2.00 spacing.
 

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427SC
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Discussion Starter #3
FFR428,

Thanks for the reply. I checked again as you suggested. The valve spacing is definitely 2.1". I also rechecked the casting number. It's possible the 6 is a 5, but the bottom of the number seems to be clearly a full circle. The F is clearly an F, not an R. The casting code runs vertically, bottom to top, to the left of the center head bolt. There are clearly five characters plus the dash: C(5 or 6)AE-F. On the right side of the head bolt is what appears to be a date code. The first character is blurred (could be 11 of H), followed by 23 (very legible) and then what appears to be a dash. It is oriented the same as the other code and also reads bottom to top. Is any of that of help?

Thanks again
 

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427SC
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Discussion Starter #4
FFR428,

The casting marks look exactly like the ones in the last photo on this link, except the date (?) code is different. Your thoughts?
C6AE-F

Thanks
 

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That's a perfect example of a slurred casting number. Those are indeed C5AE-F medium riser heads as your are as well. The Mustang Tek site is a good resource but does have a few errors. I've seen this very subject many times before. Even though they do appear to be clearly a 6 it's a 5. Ford never made a C6AE-F medium riser head. That's why I mentioned the R heads. Date code of the heads pictured is 0D15 which is 70-April-15th. The C5AE-F heads were cast and sold over the counter well into 75. I've seen date codes as late as 74. If you can send me a pic or 2 I'd be glad to take a look and let you know the date code. Original heads were cast at DIF (Dearborn Iron Foundry) and later service heads were cast at CF (Cleveland Foundry). You should see either the DIF letters for the Dearborn foundry or the CF logo for the Cleveland foundry. My tunnelport heads are 71 service heads cast at CF. Date codes on those are hard to read too. On each side of the date code you'll see a screw head that was used to attach the date code plaque to the mold. That's the dash you see more than likely. Anyway send me a pm here and I'll send you my email if you need further help and can send pics. But with the 2.1" VS those are MR heads no doubt. The C5AE-F was the only production MR heads made besides the early XE and SK prototypes. There was also a aluminum MR head which I think got a Process D type of marking.
 

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427SC
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Discussion Starter #6
FFR428,

One last observation: The intake ports are as cast (unported) and measured with digital calipers, show 2.04" in height.
 

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427SC
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Discussion Starter #7
Thanks again for te help. I will try to get a picture....it's real tight quarters....may have to use a mirror. You mentioned sending you a PM....what is that?
 

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427SC
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Discussion Starter #8
FFR428,

I used a mirror to check the other head and it is more legible. It definitely looks more like C5AE-F. The date code appears to be 9B14 which I read to be 1969-February-14th. It also has the same DIF mark that appears on the side of the block. The shorter intake port height also seems to agree with other photos I've seen of MR heads. I think I know now what I have. You have been a big help. I always built chevy engines until I bought this Cobra six years ago. It was my first introduction to the FE and it has been a real learning experience. Thanks again.
 

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I see Glenn has been a real good helper on this site !! Keep up the good work My Northern Redneck Buddy !! Here's one fur ya.. :beerbottl
It's about time you showed up here. Been a member for a while have ya?? Wes is here sometimes too. And a few other guys I know from other sites. Everybody gets around. :hy:
 
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