Has anyone ported stock magnum heads and have the before and after flow numbers .???

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I have a set of practice heads, I was wondering if they could be opened up to 250-260 CFM @ 5-6 k other wise I'll buy some new ones
 
It is at a certain amount of vacuum that is used for head
flow not RPMs.

Most major shops have machines that measure @28 inches of vacuum

.
However, we only have access to 14 vacuum due to
budget constraints

The velosity that the port generates is also important =which
is not necessarily proportional to flow (To further confuse you).
 
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Brooks James said:
I've read that stock magnum heads will do 210 CFM, at what rpm I don't know ?
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Contact Utawsome Performance. Marty, the owner has been working on these motors since they came out in 1992. He's a good guy & very knowledgeable about these engines. He'll have the answers you're looking for.
 
250-260 cfm? not easily i think. the heads are pretty limited in the pinch area....i broke trough a casting once. Cleaning up the bowl and trimming the guides are the first steps in my opinion.

Michael
 
I think people have proven the pushrod pinch really isn't a big deal on these. Maybe @MOPAROFFICIAL will give us some answers.
 
RustyRatRod said:
I think people have proven the pushrod pinch really isn't a big deal on these. Maybe @MOPAROFFICIAL will give us some answers.
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Over on Speedtalk there is a CFD thread and it proves the “pinch doesn’t matter” talk to be bullshit.

It matters. That’s why Chrysler (and everyone else) ends up with offset rockers.
 
Member 63gt iirr did a thread on stock casting magnums. I did a stock flow test 15 yrs ago on a stock casting, 209 cfm iirr peak. The pinch controls the speed , floor especially or I should say the floor is drastically effected by its size.
LA heads when around 260 cfm it doesn't matter to knock it out, why? Because by then the port is so much bigger that the pinch even maxed is too small.
That's if you have your bowl venturi just right, smallish almost tons of radius by the plug side and chamber wall.
I believe from experiance two completely different shaped bowls will flow the same up to a certain point but one will carry a far greater flow at the top and hint so everywhere else a tinge
 
Member 63gt iirr did a thread on stock casting magnums. I did a stock flow test 15 yrs ago on a stock casting, 209 cfm iirr peak. The pinch controls the speed , floor especially or I should say the floor is drastically effected by its size.
LA heads when around 260 cfm it doesn't matter to knock it out, why? Because by then the port is so much bigger that the pinch even maxed is too small.
That's if you have your bowl venturi just right, smallish almost tons of radius by the plug side and chamber wall.
I believe from experiance two completely different shaped bowls will flow the same up to a certain point but one will carry a far greater flow at the top and hint so everywhere else a tinge
 
63GT's thread on porting magnums. He skirted 260@28

www.forabodiesonly.com

Magnum head porting for the beginner

Recently, in one of my fits of boredom, I grabbed a spare test head. A '97 Magnum off of a 5.9 with 1.92/1.62 valves. As I went through my normal process of grinding and testing, I discovered how this head responds to changes. I enjoy this sort of thing. Quirky. I had fun with it. 255 cfm worth...
www.forabodiesonly.com www.forabodiesonly.com
 
Correct me if I'm wrong, but after complete reconditioning, porting of mag heads
I would have 2k in them.
 
Rat Bastid said:
Over on Speedtalk there is a CFD thread and it proves the “pinch doesn’t matter” talk to be bullshit.

It matters. That’s why Chrysler (and everyone else) ends up with offset rockers.
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If that's the case I stand corrected. Your wife is lettin you out too much.
 
Not sure if this video adds to the topic but I thought it was interesting......
 
RustyRatRod said:
If that's the case I stand corrected. Your wife is lettin you out too much.
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It's a pretty broad brush to paint with. Depends on the ports design. You can have a port that works excellent and then open up that pinch as big as you can and watch it lose all of its low lift velocity which is airflow...as with a magnum head.
If it didn't matter in that head they would have had the 308 pushrod holes and not that smaller Magnum pinch. People need to be more specific. Specifics come with understanding. You can lead somebody into making a big hole and believing that it's all about making big holes. The Magnum head is 150 CC's and it's hard to get it much bigger than 160 to 165cc. That's why this **** gets confusing because you'll have people tell you this.. tell you that ...and then tell you it's about the quality of air at the same time... not necessarily the amount of air. .. then show you a bunch of power on a Dyno with a head that falls off and doesn't have that great a quality of air. One gathers that while important..its not as important as some say it is. Not to veer off ..but Eric weingartner did a video where he turns the test pressure way up and gets the port to go turbulent sooner expressing its simulation to a running engine .... not quite. Now that leads a lot of people to believe that if you don't run an absolutely High test pressure 28-40" the entire time testing that you will not have accurate info... and while that might be partially true...neither is flowbench to begin with.
Go watch the video with the camera inside the intake manifold where the pulses are yanking back and forth ...that's not a steady flow depression is it.

All of this stuff is somewhat speculatory but it's what we use to try and measure what we're doing. So saying this or that doesn't matter and attaching nothing of specifics to it isn't very helpful.
 
I can tell you in MY experience on the china magnum head, not the good "EQ" version of old, 270 @ .500 is not to difficult, it's all valve job, (2.02) bowl sizing, guide shape, and some pinch trimming. Not what I'd consider "fully ported" but more of a well executed bowl and valve job. Not much point in doing that to a oem magnum that does and will crack. Yeah they run cracked, sometimes a long while. But eventually that crack works into the seats from my experience, and they go in the dumpster
 
@Brooks James , There's a kid on YouTube I warned him about the factory magnum heads, he didn't wanna hear about them cracking, he put a bunch of time & money into something that was probably already junk. At my work there's probably 30+ pairs to be welded and 1 single good head lol, they are junk !
If you even think about putting 2k into factory magnum heads, you might as well by me a flight from Washington to Florida so I can dump all your chardonnay down the sink lol.
Get some aftermarket heads, aluminum heads, small block **** is heavy, heavier than big block cast iron heads.
 
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