factory magnum head replacement options

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393foureyedfox

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I suspect the drivers head has the dreaded crack. It's a very good running 1995 100k motor that I hardwired into the car years ago with all the factory EFI wiring and computer. I am now looking at options to replace the heads, but don't want to do the rebuilt/crack-prone factory head again. I also do not need a performance/high-dollar head. Also, I really dont like the idea of putting some chinese crap replacement on the car either. So, what are the best options for just a stock replacement 5.9 magnum head?
 
A stock 5.9 magnum head from another junkyard engine sounds to me like your only option. There are Chinese (EQ) replacement magnum stock style heads but they are junk.
 
You say good running but suspect a crack, is there an issue ?
 
The "new" EQ heads (china) are about your only choice. With a nice valve job and a little bowl work, they aren't bad. I'd recommend getting bronze guide liners installed from the get go also.
 
pittsburghracer said:
Any flow numbers or info on these heads.
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In the 195 ish cfm from .350-.800" lift (193.3-199.6), peak @ .400"

On his bench the stock magnum flowed about 10-20 cfm better over the same range.

flow spec at 2:08

 
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pittsburghracer said:
Any flow numbers or info on these heads.
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there are tons of threads of flow numbers and performance head options out there, I'm trying to make this thread about what are the best options for a factory replacement.

I'm hesitant on rebuilding another set of factory magnums. When I got this motor, it had cracked heads but ran fine. I replaced them with a set of rebuilt heads before putting it in the car. I don't want to keep doing this. I want options for a factory replacement type head. EQ heads are now chinese? I thought years ago they were australian/new zealand. I'm not buying chinese crap, for many reasons.

If my options are basically name brand aftermarket aluminum performance heads, then price-wise, I'd have to then just look into pulling the 5.9 and putting a used recent hemi into it instead.
 
393foureyedfox said:
there are tons of threads of flow numbers and performance head options out there, I'm trying to make this thread about what are the best options for a factory replacement.

I'm hesitant on rebuilding another set of factory magnums. When I got this motor, it had cracked heads but ran fine. I replaced them with a set of rebuilt heads before putting it in the car. I don't want to keep doing this. I want options for a factory replacement type head. EQ heads are now chinese? I thought years ago they were australian/new zealand. I'm not buying chinese crap, for many reasons.

If my options are basically name brand aftermarket aluminum performance heads, then price-wise, I'd have to then just look into pulling the 5.9 and putting a used recent hemi into it instead.
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Your choice is rebuilt or Chinese or some aftermarket aluminum heads, don't see the problem with Chinese heads but it's up to you.

What problem is your engine giving that you think you need heads ?
 
From everything I've read on this head cracking thing on Magnum engines, the crack happens between the valves & is very minor. I've also been told, if it's not a race engine, don't worry about it, just keep running it if it runs well. That's what I did. The "new" EQ heads from China don't flow anywhere near as good as the originals from Australia either, from what I understand.
 
So howabout this.
20240225_181138.jpg
 
niceolddart said:
From everything I've read on this head cracking thing on Magnum engines, the crack happens between the valves & is very minor. I've also been told, if it's not a race engine, don't worry about it, just keep running it if it runs well. That's what I did. The "new" EQ heads from China don't flow anywhere near as good as the originals from Australia either, from what I understand.
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The cracks DO start between the seats, the problem is eventually, the crack migrates through the seat area, causing burned valves and a leaking seat
 
If you buy the "new" EQ heads, be SURE and disassemble and inspect, because mine were FULL of garbage
 
pittsburghracer said:
Nothing there but thanks. I’ll keep my eyes open.

View attachment 1716301778
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replicaracer43 said:
You can buy them from almost any machine shop. (Including mine) Bare castings, or complete
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Mine have the LA bolt pattern. After I took mine apart and saw the crud, after I cleaned them up I took them to my machinist and had him inspect the valve guide tolerances, and he vacuum tested each valve, checked spring heights and such. They were actually a decent head if they would have bothered to clean them.
 
318willrun said:
Mine have the LA bolt pattern. After I took mine apart and saw the crud, after I cleaned them up I took them to my machinist and had him inspect the valve guide tolerances, and he vacuum tested each valve, checked spring heights and such. They were actually a decent head if they would have bothered to clean them.
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If I bought a set they would be totally modified so every part of the heads would be gone through
 
TT5.9mag said:
Why so much interest in magnum heads as of late?
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Interesting question. Lol. I like a good challenge and actually it’s an idiotic thing to even consider with 8 set of LS heads sitting here and probably 4-5 sets of my own Speedmaster and Edelbrock heads to finish and sell. I’m not buying any speedmaster heads or taking on any this winter so I can catch up. If I take on 4-5 intakes that will keep some money rolling in and still let me catch up. So like I said it’s not a very smart thing to consider.
 
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