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Re: Hand or CNC Head Porting ???
[Re: dizuster]
#504020
10/22/09 06:47 PM
10/22/09 06:47 PM
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Anonymous
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Anonymous
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CNC porting is a program designed for a specific head, the cnc program will get you the maximum allowed porting to achieve maximum flow numbers.
a hand porter can not get each chamber exact giving you different results from head to head.
also theres a chance that a hand port job possibly could hit a exhaust port water jacket. ask me how i know. no more hand porters for me, its CNC or nothing.
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Re: Hand or CNC Head Porting ???
#504021
10/22/09 06:49 PM
10/22/09 06:49 PM
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Joined: Jan 2003
Posts: 32,394
Quicktree
I Win
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I Win
Joined: Jan 2003
Posts: 32,394
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Quote:
CNC porting is a program designed for a specific head, the cnc program will get you the maximum allowed porting to achieve maximum flow numbers.
a hand porter can not get each chamber exact giving you different results from head to head.
also theres a chance that a hand port job possibly could hit a exhaust port water jacket. ask me how i know. no more hand porters for me, its CNC or nothing.
isn't the CNC program obtained off of a hand ported port? they have to get them from somewhere 
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Re: Hand or CNC Head Porting ???
[Re: Quicktree]
#504023
10/22/09 06:57 PM
10/22/09 06:57 PM
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Joined: Apr 2005
Posts: 12,271
Overpriced Housing Central
RobX4406
I Live Here
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I Live Here
Joined: Apr 2005
Posts: 12,271
Overpriced Housing Central
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Is the cnc the right port for your application?  If porting is a one size fits all deal then cnc might be the best, but, that's not real world. cnc's are based/probed/digitized off hand ported from what I've seen.
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Re: Hand or CNC Head Porting ???
[Re: Quicktree]
#504024
10/22/09 06:58 PM
10/22/09 06:58 PM
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Anonymous
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Anonymous
Unregistered
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Quote:
Quote:
CNC porting is a program designed for a specific head, the cnc program will get you the maximum allowed porting to achieve maximum flow numbers.
a hand porter can not get each chamber exact giving you different results from head to head.
also theres a chance that a hand port job possibly could hit a exhaust port water jacket. ask me how i know. no more hand porters for me, its CNC or nothing.
isn't the CNC program obtained off of a hand ported port? they have to get them from somewhere
that is correct, lets just hope the head porter wasn't hitting the sauce or pipe when he was designing the program. 
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Re: Hand or CNC Head Porting ???
[Re: sg66mopar]
#504026
10/22/09 07:17 PM
10/22/09 07:17 PM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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CNC head porting is over rated - the shops that bought these machines have to pay for them some how and they do cut way down on shop labor costs, as hand porting is very labor intensive. I am by no means a pro when it come to head porting, but a few years back I ported a set of 915 casting small block heads. I was fortunate enough to have a brother that ran the flow room for Navistar at the time so I had unlimited access to a flow bench. We flowed the intakes in their stock configuration and found a max flow variation of 3.6%. I was able to improve this to 1.6% by doing some methodical hand porting. I'm sure that someone who does this for a living could blow those numbers away. IMO, a professional hand ported head will outflow a CNC machine ported head every time.
Fastest 300
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Re: Hand or CNC Head Porting ???
[Re: Bob_Coomer]
#504028
10/22/09 07:36 PM
10/22/09 07:36 PM
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Joined: Jan 2005
Posts: 3,635
Oakland, MI
dizuster
master
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master
Joined: Jan 2005
Posts: 3,635
Oakland, MI
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Quote:
Quote:
CNC is repeatable, but can't take advantage of making the port as big as possible because of casting shift.
Why would you want the ports larger on core shifted heads?
That's the point. CNC programs have to work on every single head, even the one's that are core shifted. That means the programs have to be conservative (small) to account for core shift. A hand porter can take advantage of a good casting...
Quote:
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A good hand porter can feel/hear when the walls are getting thin.
Really?
Now thats a skill I would love to know..Im sure its possible at the point were its almost through the side of the runner...LOL..
But at this point the heads are trashed anyways.
I kid you not, a good head porter can hear when the port wall is getting too thin. You can hear the grinder bit change pitch. I suppose grinding on heads 10 hours a day for 20 years will do that to a guy.
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Re: Hand or CNC Head Porting ???
[Re: Crizila]
#504029
10/22/09 07:41 PM
10/22/09 07:41 PM
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Joined: Jun 2005
Posts: 793
Utah
topbrent
super stock
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super stock
Joined: Jun 2005
Posts: 793
Utah
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Pick a reputable shop, either way. There are many good shops to choose from, but these guys are the perennial favorites here in Moparts-land. Hand Porting: Brian @ IMM ou812/IMM Dwayne Porter @ Porter Racing Heads fast68plymouthRyan @ ShadyDell RyanJ CNC: Jeff @ Modern Cylinder Head. Modern Cylinder Stay away from the backyard know it all types. A big mouth and a set of carbides can do a lot of damage! Do you really want to be a guinea pig for some hack? Go with the guys who have ported many sets of that that head type and have good routines and a proven history of great performance.
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Re: Hand or CNC Head Porting ???
#504030
10/22/09 07:42 PM
10/22/09 07:42 PM
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Joined: Jan 2005
Posts: 3,635
Oakland, MI
dizuster
master
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master
Joined: Jan 2005
Posts: 3,635
Oakland, MI
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Quote:
CNC porting is a program designed for a specific head, the cnc program will get you the maximum allowed porting to achieve maximum flow numbers.
Not true. Why do you think Indy offers several different CNC versions of their heads? It's because not all CNC port profiles are created equal.
Quote:
a hand porter can not get each chamber exact giving you different results from head to head.
also theres a chance that a hand port job possibly could hit a exhaust port water jacket. ask me how i know. no more hand porters for me, its CNC or nothing.
A good hand porter is not going to break into the water jacket. There are 1000's of heads ported around the country by hand that don't break into the water jacket.
CNC is used because it's fast, easy, and repeatable. That means that CNC ports are set up to please the masses. A good hand porter can tailor the port to the motor...
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Re: Hand or CNC Head Porting ???
[Re: dizuster]
#504031
10/22/09 07:43 PM
10/22/09 07:43 PM
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Anonymous
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Anonymous
Unregistered
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Quote:
Quote:
Quote:
CNC is repeatable, but can't take advantage of making the port as big as possible because of casting shift.
Why would you want the ports larger on core shifted heads?
That's the point. CNC programs have to work on every single head, even the one's that are core shifted. That means the programs have to be conservative (small) to account for core shift. A hand porter can take advantage of a good casting...
Quote:
Quote:
A good hand porter can feel/hear when the walls are getting thin.
Really?
Now thats a skill I would love to know..Im sure its possible at the point were its almost through the side of the runner...LOL..
But at this point the heads are trashed anyways.
I kid you not, a good head porter can hear when the port wall is getting too thin. You can hear the grinder bit change pitch. I suppose grinding on heads 10 hours a day for 20 years will do that to a guy.
so i guess the head porter that did my heads wasn't listening too good,leaked like a dyke.
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Re: Hand or CNC Head Porting ???
#504032
10/22/09 07:53 PM
10/22/09 07:53 PM
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Joined: Jan 2005
Posts: 3,635
Oakland, MI
dizuster
master
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master
Joined: Jan 2005
Posts: 3,635
Oakland, MI
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Quote:
so i guess the head porter that did my heads wasn't listening too good,leaked like a dyke.
I didn't say your head porter could hear it.
I said a good head porter could hear it... 
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Re: Hand or CNC Head Porting ???
[Re: dizuster]
#504033
10/22/09 07:57 PM
10/22/09 07:57 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
Quote:
so i guess the head porter that did my heads wasn't listening too good,leaked like a dyke.
I didn't say your head porter could hear it.
I said a good head porter could hear it...
i couldnt have said it any better, only thing your missing is the ex head porter.
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Re: Hand or CNC Head Porting ???
[Re: Dodgeman67]
#504036
10/22/09 08:14 PM
10/22/09 08:14 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
I'm sending my hemi heads to Jeff at Modern. 
smartest thing i've heard today.
i'll be right behind you.
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Re: Hand or CNC Head Porting ???
[Re: Dodgeman67]
#504037
10/22/09 08:22 PM
10/22/09 08:22 PM
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Anonymous
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Anonymous
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it really depends on what your building under the heads that should determine the type of porting you have done.
most CNC programs are a one size fits all and may, or may not be the best type of porting for your application.
for most of the stuff we build, i prefer hand ported heads to max out the combo for the intended purpose. pricing is generally close no matter which type you go with.
also, don't get hung up on advertised flow numbers, especially the peak numbers, as they can be all over the map. advertised numbers sell porting much like phony boloney dyno numbers sell engines. talk to some qualified people to find what's best for your individual application.
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Re: Hand or CNC Head Porting ???
[Re: moparniac]
#504039
10/22/09 08:38 PM
10/22/09 08:38 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Cnc porting with hand blending...
 this is what I do... there is quite a bit of
machine lines in the port and I take the machine lines out
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Re: Hand or CNC Head Porting ???
[Re: MR_P_BODY]
#504042
10/22/09 10:15 PM
10/22/09 10:15 PM
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Joined: Feb 2007
Posts: 1,025
Las Vegas, NV
dodgeboy11
super stock
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super stock
Joined: Feb 2007
Posts: 1,025
Las Vegas, NV
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CNC porting is only as good as the information fed into the computer, and even then it still falls short of the hand ported port that was digitized for the CNC program. I would say that on a head that has symetrical ports you could get away with a fairly good CNC ported head. But on a big or small chrysler where you have ports with opposite bias, there's only so far a CNC machine can go IF there's core shift. This is where a good head porter comes in. I like to start max effort port jobs with untouched heads. It gives me an idea of how thick the material is. If I start on a CNC'd head I have no idea how much material is left in the port and whether or not there's any core shift or not.
For something that I just want a quick port job on and consistency, I say go CNC. But if you want the most out of a set of heads, you need a good head porter. As for the debate of hearing when the material gets thin, I have experienced this on several occasions.
If you want the best CNC ported heads out there, go talk to Chapman. They are an example of CNC porting at it's best.
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Re: Hand or CNC Head Porting ???
[Re: MR_P_BODY]
#504046
10/22/09 11:09 PM
10/22/09 11:09 PM
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Joined: Nov 2004
Posts: 2,119
sc
tjmarcus1
top fuel
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top fuel
Joined: Nov 2004
Posts: 2,119
sc
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Quote:
If you want the best CNC ported heads out there, go talk to Chapman. They are an example of CNC porting at it's best.
Chapman did one set of my W-9s.... plus I sent them a
broken W-9 they ported to see if it could be repaired,
it was beyond help... they duplicated my one to
a tee.... I still touched up the machining lines,
they are the ones I picked up 2 cfm for just a short
bit of time
mike, did you have another set cnc'd by someone else, if so do you know the difference?
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Re: Hand or CNC Head Porting ???
[Re: Moparnut426]
#504048
10/22/09 11:55 PM
10/22/09 11:55 PM
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Anonymous
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Anonymous
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isn't it proven by jeff at modern that his cnc program on 906 heads outperformed a hand porter on a FAST build getting a 440-6 RR into the 10 second zone while the hand porter was only able to get the A12 RR to low 11's.  i believe thats proof enough that CNC'ing one of these heads works better then hand porting. if i were to do it again CNC'ing is my choice,hands down.
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Re: Hand or CNC Head Porting ???
[Re: TS3303]
#504051
10/23/09 12:17 AM
10/23/09 12:17 AM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
CNC'ing is not magic just a xerox machine for a digitized hand ported port. Depending on the original it is probably 95-98% as good, add some hand rubbing after to get another 2%. That being said unless your running an all out effort where you need every last hp, CNC'd heads from a top line porter are more than adequate and usually a little cheaper.
would be curious to see Jeff or others post flow #'s of the original hand port versus the digitized copy of the same port. Head type not important. would be willing to bet it is only 2-3 cfm.
and i bet cnc'ing is safer as not to go through the water jacket.
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Re: Hand or CNC Head Porting ???
#504052
10/23/09 12:27 AM
10/23/09 12:27 AM
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Joined: Nov 2003
Posts: 6,293
Rock Springs
Bob_Coomer
master
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master
Joined: Nov 2003
Posts: 6,293
Rock Springs
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My 440-1 heads CNC ported by MCH flow 380+cfm. The car went 144 mph in the 8th mile and 1.07 60ft Mid July heat. Coulda been a bit faster If I had areal converter. My Stock Hemi heads also done by MCH flow 460cfm, I am willing to bet the engine runs good also. Proof to me is the track times..Flow bench numbers doesnt mean squat to me unless the track numbers back them up  Which they have
[color:"red"]65 Hemi Belvedere coming soon [/color]
[color:"#00FF00"]557" Indy engine 1.07 60ft 144mph in the 8th 2100 lbs package [/color]
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Re: Hand or CNC Head Porting ???
#504053
10/23/09 12:37 AM
10/23/09 12:37 AM
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Anonymous
Unregistered
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Anonymous
Unregistered
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you can see by the answers here that almost everyone's take on this subject is all about peak flow numbers.
so using YOUR logic for a street hemi car with a 2800 stall convertor, 256 @.05 camshaft and 9.5-1 compression, a max port CNC hemi head flowing 460 cfm would be the cats azz? not hardly. the porting needs to match the combo. stop being so one track minded.
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Re: Hand or CNC Head Porting ???
#504054
10/23/09 01:23 AM
10/23/09 01:23 AM
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Joined: Apr 2004
Posts: 1,981
SE Michigan
TS3303
top fuel
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top fuel
Joined: Apr 2004
Posts: 1,981
SE Michigan
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Quote:
you can see by the answers here that almost everyone's take on this subject is all about peak flow numbers.
Dan! This is the last time I'm going to tell you to stay away from the coffee pot this late! Only saw one post about max flow, yes it's all about the area under the curve for a broad power curve.
Bob whats this 1.07 144 mph car? dragster or PA car?
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Re: Hand or CNC Head Porting ???
#504055
10/23/09 09:20 AM
10/23/09 09:20 AM
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Joined: Jan 2003
Posts: 75,005
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,005
U.S.S.A.
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Quote:
isn't it proven by jeff at modern that his cnc program on 906 heads outperformed a hand porter on a FAST build getting a 440-6 RR into the 10 second zone while the hand porter was only able to get the A12 RR to low 11's.
i believe thats proof enough that CNC'ing one of these heads works better then hand porting.
if i were to do it again CNC'ing is my choice,hands down.
A 10sec pass so far has only happened ONCE , Ed had a killer 60ft and has not been able to duplicate it since .
You should stick to what you know ... BBQ'ing skirt steaks ...
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Re: Hand or CNC Head Porting ???
[Re: JohnRR]
#504056
10/23/09 09:43 AM
10/23/09 09:43 AM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
Quote:
isn't it proven by jeff at modern that his cnc program on 906 heads outperformed a hand porter on a FAST build getting a 440-6 RR into the 10 second zone while the hand porter was only able to get the A12 RR to low 11's.
i believe thats proof enough that CNC'ing one of these heads works better then hand porting.
if i were to do it again CNC'ing is my choice,hands down.
A 10sec pass so far has only happened ONCE , Ed had a killer 60ft and has not been able to duplicate it since .
You should stick to what you know ... BBQ'ing skirt steaks ...
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Re: Hand or CNC Head Porting ???
[Re: sg66mopar]
#504060
10/23/09 11:21 AM
10/23/09 11:21 AM
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Joined: Mar 2006
Posts: 9,910
Eighty Four, PA
B G Racing
master
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master
Joined: Mar 2006
Posts: 9,910
Eighty Four, PA
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Quote:
Hey guys, I didn't mean to start a war here. Just wanted to go a couple seconds faster. I'm looking for all the flow I can get from the 440-1s. The motor's 572 inches with over 14-1 compression and with my new cam and rocker combo, around .780 lift. I was hoping to go with B1 MCs but just lost a big chunk of my income so now I need all I can get from my old heads without breaking the bank. I run Super Gas @ around 146 mph and brackets at around 8.90 and 150 mph, but wanted to see something like 8.60 - 8.70 at 155 or more and SG @ over 150.
Dick,no war here.You are maxed out with the 440-1s on a 572" and you would benifit to max them out with the 345cc CNC.The best head combo would be Indy -13 or B-1s or something bigger with a flow of over 400cfm.
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Re: Hand or CNC Head Porting ???
[Re: hemi-itis]
#504064
10/23/09 02:22 PM
10/23/09 02:22 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
Quote:
Quote:
isn't it proven by jeff at modern that his cnc program on 906 heads outperformed a hand porter on a FAST build getting a 440-6 RR into the 10 second zone while the hand porter was only able to get the A12 RR to low 11's.
i believe thats proof enough that CNC'ing one of these heads works better then hand porting.
if i were to do it again CNC'ing is my choice,hands down.
A 10sec pass so far has only happened ONCE , Ed had a killer 60ft and has not been able to duplicate it since .
You should stick to what you know ... BBQ'ing skirt steaks ...
John,you should stick to chasing ambulance casualties.You speak with SUCH authority like you are running in the 14's.Correct me if I'm wrong but the top F.A.S.T guys are all going to MCH.And NO!You can't have a peice of steak  
AL, i made extra steak for
JOHNAHAH at mopars at the valley but he didnt come by to say hi, dont you remember?
he knows exactly who we are but we dont know who he is!
wish JOHNAHAH introduced himself to us.i wonder why. maybe next year,oh well
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Re: Hand or CNC Head Porting ???
[Re: sg66mopar]
#504068
10/23/09 06:13 PM
10/23/09 06:13 PM
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Joined: Nov 2003
Posts: 6,293
Rock Springs
Bob_Coomer
master
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master
Joined: Nov 2003
Posts: 6,293
Rock Springs
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The engine will run good, and you wont need to spin the mill 8K either. 7000-7300 shift points and the engine will live a good while. Hey TS3303 Yes the car was a 225 inch heavy hard tail converted dirt chassis. It was heavy, and ugly..but mainly unsafe. The car had 3/4 ton disc brake calipers and Jeep rotors. LOL..High tech stuff. But it made me feel good when I would be the fastest or next to the fastest cars at the track. But they had M&M slip tube chassis and Undercover 4 link chassis, with complete Mark Williams rear parts. 600" 900-1000 hp Big Chevy's with Sheet metal intakes and twin Alky Dominators etc... LOL My junk had the single small 4150 cast Indy intake with a 4" toilet. SG66mopar That engine will run good. No need to spin the motor to 8K either... 7200-7300 shift points and it will live a long time. What rocker gear are you going to run?
[color:"red"]65 Hemi Belvedere coming soon [/color]
[color:"#00FF00"]557" Indy engine 1.07 60ft 144mph in the 8th 2100 lbs package [/color]
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Re: Hand or CNC Head Porting ???
[Re: sg66mopar]
#504069
10/23/09 06:14 PM
10/23/09 06:14 PM
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Joined: Jan 2003
Posts: 9,996
Frostbitefalls MN (Rocky&Bullw...
gregsdart
master
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master
Joined: Jan 2003
Posts: 9,996
Frostbitefalls MN (Rocky&Bullw...
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I have yet to run them, but got a solid 5% flow improvement by going to a 2.300 intake valve from 2.25, and didn't lose much exhaust flow when they cut the exhaust to 1.78 to make it work. Lets hope the $970 was worth it! Here is a flow sheet,,,,
Last edited by gregsdart; 10/23/09 06:15 PM.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Hand or CNC Head Porting ???
[Re: Bob_Coomer]
#504070
10/23/09 07:24 PM
10/23/09 07:24 PM
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Joined: Apr 2004
Posts: 1,981
SE Michigan
TS3303
top fuel
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top fuel
Joined: Apr 2004
Posts: 1,981
SE Michigan
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Quote:
The engine will run good, and you wont need to spin the mill 8K either. 7000-7300 shift points and the engine will live a good while.
LOL
My junk had the single small 4150 cast Indy intake with a 4" toilet.
SG66mopar
That engine will run good. No need to spin the motor to 8K either... 7200-7300 shift points and it will live a long time.
What rocker gear are you going to run?
I agree with the rpm's. I think that was my next hurdle in trying to run 7's with a 572" -1 motor. The 4.56 gear and 7600 rpms at the stripe were just making the head issue worse. Wanted to try 4.30's but they are always back ordered for a D60. Tall gears and let that beast grunt, try to keep it under 7200.
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