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Ford C-460 Head Flow Tech Data
December 12 2005 at 10:31 PM
No score for this post Charlie Evans (Login c.evans)
from IP address 152.163.101.9

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Ford C-460 Heads, Interesting Flow Data

Hey guys,

This is a summary of some interesting flow data on the last three sets of C-460 heads that have gone out the door from here. It’s a classic example of how the proper shape and also the necessary volume affect the flow curve of a cylinder head.

Set #1 was a set belonging to a truck puller in North Carolina. They had suffered an engine blow-up and came in here for welding and repair. They had already been fully ported by some other shop, and I don’t know who, but I wasn’t very impressed. When we got done with the welding, new seats and guides, and some new Manley titanium valves we did a competition valve job with Newen carbide cutters. The intakes were the standard 2.450" and the exhaust were 1.900". Although the owner didn’t ask me to, I threw them on the flow bench just to see how good the flowed. I was disappointed to say the least. The intakes (average of all 8 ports) flowed the following;

.200=160.4, .300=238.3, .400=321.6, .500=393, .600=440.1, .700=455.5, .800=431.5, .850=422.6, .900=417.3 cfm

As you can see after .700" lift these ports were all done and the heads stalled and went backward. This is a classic example of an improper shape on the short side radius, and "floor air" colliding with "roof air" in the bowl. So I called the owner and gave him the flow numbers and asked him if he wanted me to rub on them a little bit. I told him I wasn’t going to port the heads, but that I felt like they needed a little work on the short side radius. He said go ahead and I proceeded. I wish I had cc’ed the intake ports, but I forgot, so I do not know the volume of the intake ports on this set of heads. The new flow numbers are;

.200=159, .300=239.1, .400=322.9, .500=394.4, .600=443.3, .700=466.8, .800=449.3, .850=444.3, .900=439.8 cfm.

So the heads responded as I suspected they would and essentially it was a wash up until .600" lift and then we started seeing a little increase. By .700" we gained 11.3 cfm, at .800" we gained 17.8 cfm, at .850" we gained 21.7 cfm and at .900" we gained 22.5 cfm. While the flow numbers are still nothing to brag about, I am happy for the gains at the higher lifts and at least the port doesn’t stall as bad. I felt that additional major work would have been required to up them to the status of a rock & roll set of C-460 heads, and I did the above work for just $380, so I feel he got good value for his dollar. The lesson to be learned is that having the proper short side radius on the intakes, can easily pick up a set of heads 22 cfm.


Set #2 This set was done for a truck puller in Virginia. They were brand new and had our full CNC porting job on them. The intake valves were 2.450" Manley titanium again, and the exhaust were 1.880" Manley titanium. The intake port volume on these heads are right around 378 cc. The average of all eight intake ports flow is;

.200=154.8, .300=235.6, .400=312.5, .500=390, .600=451.3, .700=483.6, .800=496.4, .850=500, .900=502 cfm.

The valve job has a 45* seat, and was done with Newen cutters again. I am pleased with the flow numbers and feel like this is what a rock & roll set of C-460 heads should flow. I’ve been over this before, you can get bigger flow numbers at the high valve lifts with a 52* seat, but then the "seat life" is shortened. The things I want you to remember before we go to the next heads is that they were fully CNC ported with a 2.450" valve and the port volume was 378 cc.


Set #3 was a set of new C-460 heads that we did for a street driven turbocharged engine. In this case we did a reduced volume CNC porting program on the exhaust by using a .050" smaller diameter cutter. We also did the CNC program on the chambers and the pushrod program. The intakes were hand ported in the bowls only with special attention being paid on the short side radius. The intake valves were 2.425" (smaller) Manley titanium and the exhaust were 1.880" Manley XH - 430 Inconel. Our reasoning here was that the intake track was going to be pressurized and in the street/strip application nothing has to be maxed out according to my friend Roger Szabol in Winder, GA who races a twin turbocharged drag car. Also I wanted to keep the exhaust port walls a little thicker due to the extended heat, so that was the reasoning for the reduced volume exhaust port. Additionally, the cam was only going to be around .700" lift, so nothing had to flow really great numbers at the high valve lifts. The average of all eight intake ports was;

.200=160.3, .300=251.5, .400=332.1, .500=397.3, .600=442.5, .700=456.6, .800=453, .850=446.1, .900=439.6 cfm.

Notice that the intakes actually flowed better than Set #2, even with the smaller valve and absolutely no porting in the intake port at all, (just bowl porting) from .200" through .500" lift. The intake port volume was 332 cc (difference of 46 cc) and this is a classic example of the smaller port outflowing the bigger port at the lower valve lifts because the smaller port has increased VELOCITY !. The bigger port is "lazy" at the lower lift points, but then the bigger port comes on and outflows the smaller port from .600" lift on up. The valve job was again a 45* seat and was done with the exact same Newen cutter on both heads. Also notice that from . 500" lift on up, the flow curve on these turbocharged heads and the first set of heads that I repaired is very similar in cfm. The problem is the first set is being used in a pulling truck and will see .850" or so valve lift, whereas these heads won’t need to flow at high valve lifts because of the street cam.

Lem and I have "this thing" about properly sized ports and properly sized valves for different applications. We work at it pretty hard and Lem spends a lot of time in designing custom camshafts for the racers also. The bottom line is that your head selection, your cam selection, the engine’s CID, the flow curve and many more variables should be carefully chosen when you are building your racing engine. They all should be compatible with each other.

I hope you have found this interesting,
Charlie


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Jon Thee
(Login theemudracer)
152.163.101.9 Very interesting......n/m
No score for this post December 12 2005, 10:53 PM

n/m

Jon Thee

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DaveMcLain
(Login DaveMcLain)
216.229.65.178 Charlie do you feel...
No score for this post December 12 2005, 11:10 PM

Charlie I was just thinking about how the smaller port worked better at lower lifts, do you suppose this is because the velocity does not have to increase quite as much as the air travels from the port to the valve and seat area(it's already going faster) therefore it works better at low to medium lifts than the large port? Could this also be one of the reasons why it tends to fall off more at high lift with the valve mostly out of the picture, the velocity is now very high in the port and really drops when it reaches the cylinder? Making the port larger esspecially down in the bowl area might make the port work better because it makes the transisition from the port to the cylinder more gradual? Any ideas?

Which style of port is more effected by the intalation of the intake manifold, the larger one or the smaller one?? Is the larger port more forgiving if the intake tends to push the mass of the flow off center?




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Lem Evans
(Login l-evans7)
69.166.129.47 volume at the high lifts
No score for this post December 12 2005, 11:21 PM

is such that the air speed wants to see more area/shape over the short side and a bigger bowl . Otherwise the air becomes turbulant and "stalls" the port IMO .

This message has been edited by l-evans7 from IP address 69.166.129.47 on Dec 12, 2005 11:22 PM




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Gary Blair
(Login GB3351)
67.130.59.43 Charlie have you ever had the opportunity to test your small 332 CC
No score for this post December 12 2005, 11:51 PM

head vs. the larger 378 cc intake runner on the dyno and in a drag car?

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Charlie Evans
(Login c.evans)
205.188.117.68 No Gary, I Haven't.
No score for this post December 13 2005, 1:38 AM

I haven't had the right "situation" present itself so I could. We're going to dyno two engines at the end of this month, but neither one of them are "C" headed engines.

I do remember you telling me that you could make a C-460 head "work" on a small 470 CID engine. Reading between the lines, I would think that would have been a small volume runner and the engine would be "working" at some very high rpm's. The small CID truck pullers that run C-460 heads work their engines between 8000 to 9000 rpm.

Later,
Charlie

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Gary Blair
(Login GB3351)
67.130.59.43 Charlie I've only had one 477 and it made 902 @ 7100.
No score for this post December 13 2005, 8:43 AM

That was 8 years ago and a lot has changed. I would like to do another one but I don't have an opportunity either. It had 2.35 intakes and 1.80 exhausts on a 4.440 bore. The intake port was just a clean up with stock sized runner area. The same on the exhaust.

This message has been edited by GB3351 from IP address 67.130.59.43 on Dec 13, 2005 8:54 AM




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Steve S.
(Login 67xr7cat)
146.145.96.50 Do you remember how much lift the cam had? N/M
No score for this post December 13 2005, 1:21 PM



Thanks Steve S.

This message has been edited by 67xr7cat from IP address 146.145.96.50 on Dec 13, 2005 1:22 PM




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Gary Blair
(Login GB3351)
67.130.59.43 Steve it was a Comp. and probably .837 gross on the intake. n/m
No score for this post December 13 2005, 1:45 PM

n/m

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DaveMcLain
(Login DaveMcLain)
64.251.141.104 C Headed Puller
No score for this post December 13 2005, 9:28 AM

I think the C headed truck pullers around here are running a 605 and a 632 to about 8000rpm with the C heads! Now that's a bunch, I wonder how much camshaft does that take?


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Scott J. AKA the Mad porter !!!
(Login ScottJ429)
131.191.33.129 Thanxxx for sharing charlie.... Good stuff as always... n/m
No score for this post December 13 2005, 12:32 AM

n/m





Regards,
Scott Johnston / RHP

Complete list of product and services:
http://www.reincarnation-automotive.com






http://www.prepaidlegal.com/info/scottjohnston




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mikep
(Login ferdman)
198.176.189.201 Re: Ford C-460 Head Flow Tech Data
No score for this post December 13 2005, 4:01 PM

Charlie, I was wondering if I could contact you about sending my C heads in so you can look at them and see if any improvement can be made. Also I can send my hogans intake in also for your comparison testing of the intake you talked about in the earlier post.

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Charlie Evans
(Login c.evans)
64.12.117.9 That Will Be Fine !
No score for this post December 13 2005, 8:44 PM

We can take a look at them, flow test them and see if there are any cost effective upgrades we can do. I'll fax you the flow numbers then call you and we'll decide together what you want to do. The Hogans manifold sounds like a nice idea also.

The address is;

Evans Racing Engines
1231 Upper Trace
Owensboro, KY 42303

(270)685-4654

Thanks,
Charlie

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