FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: chris401 on October 26, 2013, 11:00:31 PM
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I have a set of C4AE-G and C6AE-R. I where I can get a pair of C1AE-A locally. All untouched. Which of the three would you prefer for a street/strip 428?
Thanks
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C4 or C1 for overall airflow. C6 if I needed an exhaust port to match a unibody non-CJ or pickup truck header
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I agree with Ross. C4s have nice ports, but be careful if you put hardened seats in the exhausts. It's easy to bust through to the port and lose some valve seat seating area due to the throat being very shallow on the short side.
You can get Hookers to bolt up to an 8 bolt head in a unibody car, but you either have to heat and push the bracing back against the tower or slightly notch them. Even then they might touch if the engine moves much. I have C5 MR heads in my Mach with Hookers. I heated the bracing on the R-code towers and pushed them back flat against the tower, but still have "witness" marks from the header bolts touching. That doesn't bother me.
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Is there any difference in flow from the
C1s to the C4s? I have both and i cant see
any big difference betwen them--
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So the C6-R heads have the "misaligned" exhaust ports like the C8AE-H? So much for the R heads being "poor man's CJ". Or am I reading this incorrectly?
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Its going in an F100. Not any time soon, just getting rid of any thing that wont be used. The 16 bolt pattern did look appealing for a good header seal but Ill probialy drop the money into a good set of 8 bolt pickup headers.
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So the C6-R heads have the "misaligned" exhaust ports like the C8AE-H? So much for the R heads being "poor man's CJ". Or am I reading this incorrectly?
Here are some great pictures of various exh ports.
http://www.network54.com/Forum/74182/thread/1382824243/More+exhaust+port+location+pics.
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So the C6-R heads have the "misaligned" exhaust ports like the C8AE-H? So much for the R heads being "poor man's CJ". Or am I reading this incorrectly?
Ive never owned CJ heads but I can say that the Chicago Foundry C6AE-R heads I had were slightly off from the H, D and G exhaust port location. Learned this when I bought some truck headers and found they would only mate well (compared with the above 3) with the C6AE-R location. Ill dig up the pictures and mesurements in the next couple of weeks and post here.
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So the C6-R heads have the "misaligned" exhaust ports like the C8AE-H? So much for the R heads being "poor man's CJ". Or am I reading this incorrectly?
Despite the exhaust ports the C6AE-R heads are still worth using. The Thunderbird engine that I used as one of the dyno mules for my book had C6AE-R heads, and they were nearly identical in flow with my stockish 428CJ heads. They had received only minor porting work on the roof of the exhaust. The flow data is in the dyno mule chapter of the book. I would definitely still consider them the poor man's CJ head, although the C1 and C4 heads being discussed here are probably better.
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Here is the first rule I like to say with FE heads. ANY well ported FE head can support well over 500 hp.
However, when you get to unported stuff, the raised runner emissions/unibody/truck (C7AE-A, D2TE-AA, C8AE-H) are limited to about 400 hp. Mostly because of crappy obstructed bowls, but also because of sma;; intake runner size for a deep breather.
Again though, port them and rock and roll, with just a mild rub and decent valves, I am getting 277 cfm at .550 out of a set of D2s, arguably some of the poorest performing iron heads out of the box.
C6AE-R is an odd one though, especially on the exhaust side, they have a raised exhaust floor AND a lowered roof, but they have the good early intake port. In addition, they also have the ability for the CJ exhaust bolt pattern. They are NOT like a C8/D2, they basically have a smaller port at exit, and can be opened to either an erarly/CJ or a GT/truck gasket. Pic from the FE forum
(http://i116.photobucket.com/albums/o10/427wedge/IMGP4517.jpg)
So that makes it a very universal head, it can match any of the exhaust port locations, it can match any of the exhaust bolt patterns, and it has a decent intake port. With porting, like any other head it responds well
So it is absolutely a poor man's CJ, but not because of some magical performance, but because once you get grinding on that exhaust port roof, drill the additional holes, put the big valves in, you now can run CJ headers, and have a basic design much like a CJ.
Or, you could call is a Poor Man's hipo GT or hipo truck head too, by doing the same thing, but leaving the exhaust roof low and working the floor a little and drill for GT pattern
For a truck though, be certain you know which header location you have. I used D2s because they were a perfect match to my Hedman headers and really, knowing we would port them, it was just as easy to use a known good set of heads. If your headers don't match, you'll be crying later because it will take some level of effort to make them seal, where the correct port is bolt and go.
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Maybe the C1AE's? Had a pair long ago and many think, like I did, they were about the best stock iron heads around. Still, even though the intake port size, and to a lesser degree, the shape looked good, this means nothing in terms of true airflow. I wonder if JDC (Joe Craine) has any supporting airflow data.....would be interesting to see flow comparisons among the unmachined FE
heads mentioned in this blog.
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Thanks much for the C6-R lesson. I ask because I have a rough/bare pair of these and some other parts sitting around and considered throwing them together to see what would happen. I did this once before, with the C8AE-H heads, and realized too late that the exhaust port location limited their application and/or header alignments. Sounds like I can massage these R heads to work well and line up better than the H heads.
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You may want to look at the Stan Weiss cylinder head web site
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Stan's site is very good, and he is a great guy too. However all of his data is from different benches, so it's a bit hard to really compare apples to apples.
I do use it though, especially when you are looking for potential of a more common head, because he usually has a few examples of each
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http://users.erols.com/srweiss/index.html
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You may want to look at the Stan Weiss cylinder head web site
Very interesting! Thanks for the tip. No C6-Rs listed though. Maybe I'll send mine to Les Schmader and we'll have some data.
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Good point, forgot myself about Stan's great site. Agree that some are apples/oranges due to testing variances but it's still better than nothing and it does provide ballpark info.
I do know that late(r) model SBF head statistics, for Clevelands and Windsor, are pretty much spot on, likely due to the fact that so many shops retail them, the volume sold is quite high, at least for the W heads, and the tests were (mainly) done on very late model flow benches at the now industry standard of 28".
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I have a set of the c4ae heads with the cobra jet valves installed, other than that they are bone stock. We took several sets to get flowed, here are the numbers. C4 were 247 cfm at .620. Edelbrock with mild clean up 253 at .600. Also flowed two sets of dove medium risers, stock one flowed 303 at 600 with 30 degree valves while ported head with 45 degree valves flowed 342 cfm at 600. My head guy thought with 45 degree valves in the c4 head with porting he could get in the 280 range.
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I have a set of the c4ae heads with the cobra jet valves installed, other than that they are bone stock. We took several sets to get flowed, here are the numbers. C4 were 247 cfm at .620. Edelbrock with mild clean up 253 at .600. Also flowed two sets of dove medium risers, stock one flowed 303 at 600 with 30 degree valves while ported head with 45 degree valves flowed 342 cfm at 600. My head guy thought with 45 degree valves in the c4 head with porting he could get in the 280 range.
This is the sort of info that I wish could be gathered into a type of spreadsheet and "stickied" for the forum. That sort of info is priceless, but is so difficult to come across when searching. There has been so much flow data posted over the years, but most is lost over time. Stans sight is nearly impossible to comprehend or organize into useful info unless you hand pick the pieces, write them separately on another piece of paper and try to decipher what is "useable".
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I soon getting a set of heads ported either the C1 s or the
C4 s interesting to see whats the results are
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True but Doug, Stan sells the his copyrighted data (all of it) for a mere $34.00. See the top of the home page and note that he'll even download the data into your fav spreadsheet format. Now for the FE due to limited # of heads available even today, you're right in that it's easier and maybe more cost effective to copy same down and make you own spreadsheet.
When one looks down the page, it's amazing how many SBF (sorry!) Windsor heads are available these days, as it rivals the pages of SBC heads! Where the heck were all these head suppliers I ask in the 70's? I imagine that the SBC would not still be so dominate today had Ford enthusiast had anywhere near this number of heads, and attendant engine parts, to choose from.....yikes!
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I'm having a set of C6AE-R's ported right now.....I'll throw up results as soon as I get them.
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I think cjshaker is onto something. Good info is hard to find. That's why stan's head info and jay's intake info is so important for the fe. It would also be great to have more actual numbers from cam upgrades, ignition,carbs and headers on everything from daily drivers, towing and all out race. It sure would make the fe a more viable choice for rebuild than swapping in a 460 or Windsor which has no shortage of info.
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There are Big "R" heads and small "R" heads.... I remember the Big "R" heads are the ones you want....But I cant remember why.... JMHO
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So the C6-R heads have the "misaligned" exhaust ports like the C8AE-H? So much for the R heads being "poor man's CJ". Or am I reading this incorrectly?
Ive never owned CJ heads but I can say that the Chicago Foundry C6AE-R heads I had were slightly off from the H, D and G exhaust port location. Learned this when I bought some truck headers and found they would only mate well (compared with the above 3) with the C6AE-R location. Ill dig up the pictures and mesurements in the next couple of weeks and post here.
Cleveland Foundry, not Chicago's.... ;)
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How can you tell where they were cast?
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If there is a DIF cast on them they are cast at
Detroit Industrial Foundry and if you have a
C encircling an F(if my memory is right)
they are cast in cleveland
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I like the G heads, only because I have used alot of them. They are 12 cc's more volume than the R head. Closer to the size of a CJ or LR head. In ported form, they will all flow about the same. The exhaust port is a little nicer in both early heads, unless you find 6090-R's which do not have the "ledge" at the exhaust flange. I did a 464 stroker four or five years ago with 352 HiPo heads that I ported some that made 550 hp with a flat tappet cam...........the point being that all of the production FE heads can do that if you do them right, and put the right junk underneath and on top of them. If it is a truck engine, and a pump gasser, I would lean toward the D2's with some work here and there. The smaller raised intake port is a plus for a driver, especially if it is not a big stroker.
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I've played with the early heads and the later "truck" heads..... rite now im just happy with any of the garden variety heads that hold water... I agree with blair that the smaller engines seem to work well with the later truck heads when worked over correctly... for making more power with something bigger than 400 inches I would probably lean towards the early heads unless max power wasn't a concern.... That being said I have a 450ish inch engine with the later truck heads going on it that is going to see the dyno over the winter... it seemed to be an overachiever before it split a cylinder in the pulling truck... I guess there aren't any bad fe heads really.... just some are suited to certain combinations better than others. Comes down to what the end user wants the engine to do and not do...
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I've found some heads marked simply c6ae R and some that include the 6090 on the opposite side - dot they both flow the same or are the ports different? Also some are 14 bolt vs 8 if the holes are drilled, will pick up headers line up? Thx
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I've found some heads marked simply c6ae R and some that include the 6090 on the opposite side - dot they both flow the same or are the ports different? Also some are 14 bolt vs 8 if the holes are drilled, will pick up headers line up? Thx
I pulled a set like that of a 66. One was Chicago foundry and the other was Detroit. I wondered the same thing.