New Magnum heads for 347 with Flow data

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RAMM

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So with plenty of interest in seeing what an ECONO 347 would do with Magnum heads on it in lieu of the '302's I ordered some. These are new castings from a new company. They are priced well and here is the overview.

The good: New castings
Low cost
Availability
OEM appearance (I think these are cast from OEM core boxes)
Seat inserts both intake and exhaust

The not so good: Rough casting surface
Casting is OEM replacement not performance oriented
Relatively poor flow (compared to an EQ)
Valvejob is way undersized

The goal here is to give these a performance oriented valve job with basic bowl blending using stock Magnum valves 1.92"/1.62" and achieve a good balance of flow vs. cost (time and or money).

While flow is important, it is also important to identify and not lose sight of the intended use with 347 cubic inches in mind. Here are a few pics and preliminary flow numbers.
 

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Barely get a finger between that pinch, give me the notion that they widened the lower portion of the push rod wall to slow what the pinch speeds up.
Just thin the divider/straight wall when the pinch ups the fps too much and or corks the flow. And good idea with seats on both int/exh to keep the cracks from happening in the common spots.
 
I flowed them on a 4" bore as they came out of the box using a reconditioned set of valves that came out of a set of cracked Magnums.

All testing is done at 28" of H2o

Intake Exh
.1 58 53
.2 115 102
.3 165 135
.4 192.2 135
.45 193 136
.5 193 136
.6 188 137

The stock valve job was very small .040" from the edge of the valve and the throat percentage came in at 84.6% of 1.92"

As you can see the numbers are on par with a stock set of Magnums.
 

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Not so good OOTB. Be interesting to see the improvements with a good VJ and the corresponding clean up work.
 
Here I went straight to a decent valvejob with no backcut or blending at all. This is just to answer some questions some may have.

Int Exh
.1 65 50
.2 122 95
.3 167 130
.4 194 135
.45 194 136
.5 192 137
.6 190 138

By now the port is way too fast and fairly turbulent. Worth noting is the exhaust. Even after a really nice cut from the seat to the throat the flow didn't really pick up hardly at all, However it was super quiet and I mean super quiet from .3" -.6" .

Before valve job is on left, revised is on the right. J.Rob
 

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skrews said:
Not so good OOTB. Be interesting to see the improvements with a good VJ and the corresponding clean up work.
Click to expand...

I try to tell people this, but Hughes and other big namers post flow numbers from miracle castings that have 7angle valve jobs done with proprietory cutters.

If you search on this site you will find threads with stock la head numbers that are way better than these, and with a smaller 1.88 valve.

http://www.forabodiesonly.com/mopar/showthread.php?t=221217&highlight=360+head+flow

http://www.forabodiesonly.com/mopar/showthread.php?t=145748&highlight=360+head+flow

Both tests of those factory smaller valve La heads flow better than factory magnum heads.

Thank you op for not only sharing your build , which is pretty cool btw, but also giving non biased independent information. These are the numbers most of us non famous operators of a flow bench get with ootb magnums.
No doubt that when you get done with them they will flow like they should have to begin with.
I'm not sure why Chrysler chose to produce a head thats ahead in the stem size, chamber, and exh port department...but cripple it as cast with that crummy int port...its like they just reversed the good intake bad exh.
 
So without changing a thing I pulled the head off the bench and back cut the intake valve to show how that influenced the flow.

.1 65
.2 129
.3 176
.4 192
.45 191
.5 189
.6 189.5

So as you can see while low lift flow was improved significantly, it also exasperated the turbulence as a result of increased air speed. J.Rob
 

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^ Well put.

I wish casting quality control, coming out of these companies was better. It would really improve everything, even with the not so sharp valve job.

That is one department that I think most companies could stand to improve on.
 
After the backcut I really wanted to perform a rudimentary bowl blend. When I say rudimentary I mean less than 5 minutes with a carbide. Again we start to see massive improvements only to be thwarted by turbulence. I know where the cork is.

.1 63
.2 130
.3 180
.4 201
45 194
.5 193
.6 193

So while turbulence is occurring sooner the port doesn't stall all that bad. This can be improved upon easily--The question is--What kind of flow characteristics do we need out of these heads to make the power required?

So 347 cubes and let's say 375hp and 400+ ft/lbs from 2500-5000 rpm. What do you guys say it needs?

Here's a crappy pic of the bowl blend job. J.Rob
 

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Forgive my ignorance...but are you saying these aftermarket replacements are worse than OEM units?

I'd kinda like to see some JY OEM heads to help fulfill the budget criteria.
 
RAMM said:
After the backcut I really wanted to perform a rudimentary bowl blend. When I say rudimentary I mean less than 5 minutes with a carbide. Again we start to see massive improvements only to be thwarted by turbulence. I know where the cork is.

.1 63
.2 130
.3 180
.4 201
45 194
.5 193
.6 193

So while turbulence is occurring sooner the port doesn't stall all that bad. This can be improved upon easily--The question is--What kind of flow characteristics do we need out of these heads to make the power required?

So 347 cubes and let's say 375hp and 400+ ft/lbs from 2500-5000 rpm. What do you guys say it needs?

Here's a crappy pic of the bowl blend job. J.Rob
Click to expand...


What's the aim for lift or limit?

What gear and accessories?

Flow them with the intended intake manifold.

220 cfm by .400-.450 will easily make 375 hp with a cam in the 220's @.050 and .475 lift.
Exaggerate to end up where you need to be.
 
Clean up the short side and tickle the guides a bit, and I bet they'll be in the 220 ballpark. Bench racing LOL gotta love it.
 
skrews said:
Clean up the short side and tickle the guides a bit, and I bet they'll be in the 220 ballpark. Bench racing LOL gotta love it.
Click to expand...

Totally agree. These particular Magnums pale in comparison to the EQ's which move and honest 237-238 cfm ootb with nothing but a valve job touch up. Oh and they don't stall they just plateau. J.Rob
 
RAMM said:
Totally agree. These particular Magnums pale in comparison to the EQ's which move and honest 237-238 cfm ootb with nothing but a valve job touch up. Oh and they don't stall they just plateau. J.Rob
Click to expand...

The one stock Magnum I tested years ago is just a few numbers better on the intake (202 peak) and about 10 better on the exhaust. I'm guessing the seat inserts are somewhat to blame for the less than average Magnum flow numbers. None the less some quality time with the carbide will whip them into shape. Who's castings are these and what do they cost? If you don't mind my asking.
 
Hi J. Rob, I am fascinated by your testing. I hope you don't mind but I took the liberty to graph your results so I can see them side by side.

Feel free to tell me to stop. :)

Thanks for sharing.

AlV
 

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As far as seat inserts go they have been a positive influence on flow, not a negative.

The castings have major core shift issues 'why we have some that crack and some that dont'. A grinder to the short side will greatly improve them.
 
Hebrews10:26 said:
As far as seat inserts go they have been a positive influence on flow, not a negative.

The castings have major core shift issues 'why we have some that crack and some that dont'. A grinder to the short side will greatly improve them.
Click to expand...

I've seen it help and hurt. Its all in the execution of the seat used and the install job. Most of the circle burner guys that run "unported" Vortec headed Chevys won't touch the ones that came with hard seat inserts because of the poor mid lift flow.
I'd bet the seat install job on these heads created some mismatched ledges/steps for the air to run into. Nothing that can't easily be blended out though.
 
Best down to earth info,seen in a damn long time(on Magnums). Thank you ,Ramm. FWIW,what is the intake runner cc out to. I have heard of smaller than stock Magnum 153 c.c. replacements?...
 
AlV said:
Hi J. Rob, I am fascinated by your testing. I hope you don't mind but I took the liberty to graph your results so I can see them side by side.

Feel free to tell me to stop. :)

Thanks for sharing.

AlV
Click to expand...

I don't mind at all but you could leave the exhaust flow off the chart to help make it a little easier to interpret. J.Rob
 
Abodybomber said:
Best down to earth info,seen in a damn long time(on Magnums). Thank you ,Ramm. FWIW,what is the intake runner cc out to. I have heard of smaller than stock Magnum 153 c.c. replacements?...
Click to expand...

Thankyou A-Body Bomber. I think those with some real world experience will appreciate this info. There will be no "fluff" as "fluff" does not serve anyone. I will cc the runner in a bit and post that as well. They do appear awfully small. This wold be why velocity at the apex of S.S. was over 400 f.p.s.! J.Rob
 
I like the graphing, good work. A seperate intake and exhaust graph would be good. As since the OP isn't done with the mods yet, as I see it. Correct?

Keep up the good work!
 
RAMM said:
I don't mind at all but you could leave the exhaust flow off the chart to help make it a little easier to interpret. J.Rob
Click to expand...

Sure, I can do that.

The next graph will display only the intake data.

-AlV
 
rumblefish360 said:
I like the graphing, good work. A seperate intake and exhaust graph would be good. As since the OP isn't done with the mods yet, as I see it. Correct?

Keep up the good work!
Click to expand...
Sounds good. I'll split the Intake and Exhaust data and create separate graphs.
 
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