I know that the stock Magnum heads on the 5.2/5.9 liter engine block can flow around 190 CFM, but what I am wondering is wheter or not anyone here has any experience porting and polishing heads. I've read recently that the stock Magnum heads have the potential to flow around 275 CFM after a good port and polish, but I have no experience doing this kind of work. Thus I am looking for as much information as possible so that I can attempt this miraculous feat. I will practicing on a set of old salvaged heads I found. Any help would be appreciated. Thanks

 

Here's some archived information on Magnum head flows
from various sources:
================
originally posted by
RyanJ
Shady Dell Speed Shop
Loc: State College, PA

Actually while the electricity was off here
ALL FREAKING DAY.......
I did manage to CC a Magnum Chamber.
63 CC's as cast.

Just received the 8MM valves this afternoon.
Here are the initial results,
1.92"/1.625" MP stainless valves, straight 45*,
these are a set of Dodge Truck Magnum iron heads:
Casting #'s that I saw were a 5300 and a 6671 cast
on the top of the # 1 and 3 intake runners.
Looks like a 1995 Casting.

LIFT----AS CAST
---------IN/EX
.100"--67.3/N/A
.200"--131.3/97.3
.300"--185.6/132.5
.400"--212.5/144.9
.450"--213.9/146.3
.500"--212.2/146.3
.550"--212.5/146.3
.600"--213.9/146.6
.650"--214.2/147.3
.700"--215.3/147.3

after custom porting

LIFT------IN/EX
.100"--67.3/N/A
.200"--132.8/115.6
.300"--196.0/156.6
.400"--225.0/172.2
.450"--238.1/174.3
.500"--250.5/176.6
.550"--257.1/178.0
.600"--259.1/180.8
.650"--259.1/180.8
.700"--259.8/180.8
===============

65Dart: those flow #'s are'nt off of my flowbench so, comparing them directly
to these magnums is kind of tough. Here are some #'s off my bench if you wnat
to compare:

From left to right: Magnum, Full port 2.02 "587" J head that has ran 11's,
Edelbrocks I did for Coke Bottle Kid, and a set of Large port Commando's I
just did.

LIFT--MAGNUM---"587"----EBROCK----COMMANDO
.100"--67.3-----62.1-----65.6------69
.200"--132.8----135.2----135.2-----140.1
.300"--196.0----198.7----197.7-----202.5
.400"--225.0----239.8----233.2-----246.4
.450"--238.1----253.9----245.0-----266.0
.500"--250.5----258.4----255.3-----277.1
.550"--257.1----264.9----265.7-----281.2
.600"--259.1----254.6----274.6-----282.9
.650"--259.1----N/A------279.1-----283.0
.700"--259.8----N/A------283.9-----285.3

In all fairness to the Magnum, all 3 other heads have 2.02 valves..... and the
"587" J heads are the best low/mid flowing J heads I have ever done, so that
is kind of misleading. They just ended up being a REALLY good set of heads.
And you can see why IMO the Large Port Commandos are such a great head for the
$.

For a more "fair" comparison, here is "Valcuda"'s "596" J heads with full port
work and 1.88 Tulip valve next to the magnum:

LIFT--MAGNUM---"596"
.100"--67.3---58.7
.200"--132.8--120.1
.300"--196.0--182.9
.400"--225.0--225.6
.450"--238.1--238.1
.500"--250.5--241.5
.550"--257.1--247.0
.600"--259.1--248.8


And I'm not even going to bother listing race heads as that is comparing
apples to oranges. I'll just say, a W-5 has absolutely KILLED every other race
head other than a W-8 that has been on my bench.
=====

pictures comparing stock Magnum to Magnum RT cylinder heads

http://www.geocities.com/alwest_83/magnum.html

====
posted by
BigBlockRanger
Jig meister
Loc: Amarillo, Texas

Do you have any of your other as cast numbers available for comparison's sake?
302, J, X, W2, W5, etc.?
There's probably alot of guys that will not do ANY porting and want to know
if they are worth the conversion $.

That being said...

MORE, MORE, WE WANT MORE!

Oops I think I found some of them:

302's
LIFT----I-------E
0.100--55.2----34.5
0.200--105.2---70.7
0.300--152.0---104.2
0.400--187.0---113.2
0.450--189.8---115.5
0.500--190.1---117.3
0.550--190.4---119.0
0.600--190.4---120.4

596's
LIFT----I-------E
.100--62.8----48.3
.200--117.3---98.3
.300--174.2---120.8
.400--193.2---125.6
.450--192.5---127.7
.500--192.5---128.3
.550--192.5---129.0
===========
posted by
65Dart270
top fuel
Reged: May 31 2003
Loc: Amarillo, Texas

OK, after looking at the initial numbers,
I was pretty impressed.
However,
I went back and dug through the archives and
found all the "ported" and "as cast" flow numbers I could,
and those Magnums stack up very well.
I was very impressed when I saw the ported 915 #s:
Lift Int/Exh
.100 61.9/58.4
.200 134.3/115.2
.300 190.2/141.4
.400 233.4/157.8
.500 258.9/172.3
.550 267.9/175.5
.600 273.9/181.9

Comparing the Magnums to these,
the Magnums were very close,
and the Magnum R/T's with the 2.02 valves
should theoretically outflow the 915's.
Now THAT would be pretty impressive.

--------------------
"Although prepared for martyrdom,
I preferred that it be postponed."
Sir Winston Churchill
===========
More tidbits for the smallblock stew brewing here. My dad runs the Mopar
Performance iron heads that were discontinued awhile back. He bought them bare
and had them ported and fitted with Manley chevy valves with the smaller stem.
Intake 28" h2o 1.96 valve:
.100= 74.7
.200= 140.9
.300= 193.5
.400= 224.2
.500= 242.0
.600= 242.2
Exhaust 1.60 valve
.100=53.1
.200= 107.1
.300= 147.2
.400= 167.0
.500= 177.6
.600= 182.3
I'll try to dig up a part number but I believe they were the old "swirl port"
head. He has just bought some w-2's for next years project. "As is", they
didn't flow any better than the heads he's running now (same bench).

 

HankL, Thanks for the quick reply. I do appreciate it. You seem to have read as much as a Chrysler engineer on the subject matter of automotives from what I can tell from your posts being so complete.

 

One thing though, does anybody know of any tips and tricks for when it comes to doing a home port and polish job? I'm trying to attempt a modest port and polish out of my garage.

 

There are 'templates' that were sold up to a few years ago by Mopar Performance that you try sliding into the ports as you grind until the templates fit.

You can find these for sale on eBay every now or then.
The ebay auction below is not for the 1992-2001 Magnum engines
but are examples of a similar thing:

http://cgi.ebay.com/ebaymotors/Mopar...spagenameZWD1V