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Re: Anything to gain by porting Edelbrock RPM heads?
[Re: Cab_Burge]
#1292513
08/28/12 01:20 AM
08/28/12 01:20 AM
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Joined: Oct 2003
Posts: 3,698
NE Oklahoma
Von
master
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master
Joined: Oct 2003
Posts: 3,698
NE Oklahoma
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Some of the RPM castings OOTB are as poor as mid 260s. IIRC, modern can get 320ish out of em CNC'ed. That would make a monster difference on a 500 incher.
72 RR, Pump gas 440, 452s, 3800 lbs, Corked, ET Radials,. 11.33@117.72.
Same car, bone stock 346s, 9.5 comp, baby solid. 12.24@110.
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Re: Anything to gain by porting Edelbrock RPM heads?
[Re: Kern Dog]
#1292515
08/28/12 01:36 AM
08/28/12 01:36 AM
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Joined: Aug 2003
Posts: 43,124
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,124
Bend,OR USA
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Quote:
Can someone elaborate a little about CNC porting? I seem to bypass most magazine articles on porting, but I seem to recall that it involves a computer programmed machine instead of porting by hand?
If so, I suppose the advantage is a more consistant port size from cylinder to cylinder?
I think that all of the CNC programs are based on hand porting two cylinder ports, a left and right hand port(I hope that makes sense  ) to get the optimum flow and then have the CNC probe measure and store all the numbers in its memory and make all the other ports match those two, one left hand and one right hand   If I'm wrong I hope someone will correct me Jeff, Dan, Todd?
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Anything to gain by porting Edelbrock RPM heads?
[Re: Kern Dog]
#1292516
08/28/12 03:04 AM
08/28/12 03:04 AM
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Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo
Too Many Posts
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Too Many Posts
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
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Quote:
Can someone elaborate a little about CNC porting? I seem to bypass most magazine articles on porting, but I seem to recall that it involves a computer programmed machine instead of porting by hand?
If so, I suppose the advantage is a more consistant port size from cylinder to cylinder?
Basically the machine does it. With the computer in control, results can be duplicated and guaranteed.
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Re: Anything to gain by porting Edelbrock RPM heads?
[Re: Jerry]
#1292521
08/28/12 12:33 PM
08/28/12 12:33 PM
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Joined: Jan 2003
Posts: 74,976
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,976
U.S.S.A.
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Quote:
whats the next head up from the edelbrock. is it worth upgrading the heads instead of cnc porting?
I would think an Indy EZ
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Re: Anything to gain by porting Edelbrock RPM heads?
[Re: JohnRR]
#1292522
08/28/12 01:04 PM
08/28/12 01:04 PM
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Joined: Feb 2005
Posts: 20,159
PA.
pittsburghracer
"Little"John
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"Little"John
Joined: Feb 2005
Posts: 20,159
PA.
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A good Friend of mine is clicking off 8.90's in his duster with a set of ported edelbrock at 2500#. I should add that he did this the last few weeks in terrible air. 
Last edited by pittsburghracer; 08/28/12 01:06 PM.
1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27
Livin and lovin life one day at a time
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Re: Anything to gain by porting Edelbrock RPM heads?
[Re: dogdays]
#1292523
08/28/12 05:00 PM
08/28/12 05:00 PM
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Joined: Nov 2004
Posts: 3,544
Syracuse,NY
CompWedgeEngines
master
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master
Joined: Nov 2004
Posts: 3,544
Syracuse,NY
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Quote:
With the right cam and heads your 493 will make 600 hp, actually it shouldn't be hard. To get there you need around 300 cfm at 28" depression, the standard. You are at 260-270 now. an extra 30 cfm can mean more than 60 hp.
Think about it...if you built a stroker you must have wanted more power. Porting the heads is a proven way to get there, you would notice the difference with the cam you have now.
Going "the next step up" in an Edelbrock head puts you into the realm of offset rockers, more on the race side. I'd say don't do it unless you are a strictly quarter mile guy.
Jeff at Modern Cylinder heads seems to have the program for CNC porting these heads. As said above, a CNC program starts with an optimized port. It is then measured and the dimensions changed into directions for a computer numeric controlled milling machine. The machine does every port the same and it doesn't require a skilled individual to do it by hand. The net result is the best port for every cylinder. The hard part is getting the right port and making a program.
R. [/quoI agree 100% with Dog. Why bother stroking it then? Its a 493, let it breath.
Another example, such as Johns above, but totally different car, 3600# leaf spring foot brake bracket car, has gone 10.06 @132+, and goes and goes and goes. Not even really optimized, because its in bracket mode. Uses a shelf .650 Comp cam. Heads were 296@.550, 304 @ .600
The Eddy heads work very well. These heads were hand ported.Stuff it in the 2500# Duster below, and probably similar results, although I'd think the Duster has more lobe seperation and more lift, just guessing.
RIP Monte Smith
Your work is a reflection of yourself, autograph it with quality.
WD for Diamond Pistons,Sidewinder cylinder heads, Wiseco, K1 rods and cranks,BAM lifters, Morel lifters, Molnar Technologies, Harland Sharp, Pro Gear, Cometic, King Engine Bearings and many others.
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Re: Anything to gain by porting Edelbrock RPM heads?
[Re: pittsburghracer]
#1292524
08/28/12 05:02 PM
08/28/12 05:02 PM
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Joined: Nov 2004
Posts: 3,544
Syracuse,NY
CompWedgeEngines
master
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master
Joined: Nov 2004
Posts: 3,544
Syracuse,NY
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Thats awesome John...did you do those heads? .700 ish lift? Electronics or Non Electronics car? How many CI" ?
RIP Monte Smith
Your work is a reflection of yourself, autograph it with quality.
WD for Diamond Pistons,Sidewinder cylinder heads, Wiseco, K1 rods and cranks,BAM lifters, Morel lifters, Molnar Technologies, Harland Sharp, Pro Gear, Cometic, King Engine Bearings and many others.
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Re: Anything to gain by porting Edelbrock RPM heads?
[Re: Jerry]
#1292525
08/28/12 05:51 PM
08/28/12 05:51 PM
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Joined: Oct 2011
Posts: 559
Idaho
LaRoy Engines
mopar
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mopar
Joined: Oct 2011
Posts: 559
Idaho
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Quote:
whats the next head up from the edelbrock. is it worth upgrading the heads instead of cnc porting?
It depends upon how far you want to go. If you already own the RPM head, it can be hand ported to make 787 HP on a 451ci all motor, pump gas engine. To get that much from another head, you have to get the new head AND have it ported.
If you are looking for beyond 700 HP you should start with something other than the RPM head. If you already own them, 750 HP isn't beyond their capability.
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They didn't have a interest or a dog in the fight in the results 
