Magnum heads worth the effort?

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Freezerman

Freezerman

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I currently have a 1974 360 with an untouched bottom end so pistons are down the cylinder. It has X heads on it that are measured at 68cc, and an XE268 cam, early 340 exhaust manifolds,2800 stall with 3.73 rear, 26" tires. It runs great for what it is but I would like more of course. Would I get much gain with changing to fresh Magnum heads for better compression and flow? I could get a fresh set for $400. I don't want to spend the money on EQ heads for this motor,
 
@MOPAROFFICIAL can give you some real numbers on flow instead of opinions from the hip. I tagged him so give him a bit to chime in.
 
Just remember with Magnums, you will need a different intake, lifters and pushrods to make them work.
 
Yeah, thanks. I was thinking of getting a different intake anyway. My comp lifters I think had oiling holes so I should be able to measure some pushrods.
 
RustyRatRod said:
@MOPAROFFICIAL can give you some real numbers on flow instead of opinions from the hip. I tagged him so give him a bit to chime in.
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He won't find much more than the chamber diff in size if he already has 2.02 x heads.
They're 68cc he says. I know they flow at worst 218 cfm peak. Set of mags i flow tested peaked at 204-209 cfm.
How big the mag chamber in comparison might be the final blow. Probably not much diff other than shape. I'd stay with the x heads in this case. The cost/trouble to change over is close to no diff or worse.
 
Freezerman said:
Yeah, thanks. I was thinking of getting a different intake anyway. My comp lifters I think had oiling holes so I should be able to measure some pushrods.
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Did you see the thread that I had on the Speedmaster heads? They have an offer right now with a free and take as well...
 
Freezerman said:
I currently have a 1974 360 with an untouched bottom end so pistons are down the cylinder. It has X heads on it that are measured at 68cc, and an XE268 cam, early 340 exhaust manifolds,2800 stall with 3.73 rear, 26" tires. It runs great for what it is but I would like more of course. Would I get much gain with changing to fresh Magnum heads for better compression and flow? I could get a fresh set for $400. I don't want to spend the money on EQ heads for this motor,
Click to expand...
I have a set of mag heads ready to try on a LA. Don't know when I'll do the swap, but it's going to happen. I have the pushrods (they were like 99 bucks?), lifters (but most aftermarket lifters oil through anyways, so maybe you wouldn't need them), and I installed the Hughes spring kit, good to .550 lift on a stock mag head. I did massage the pushrod pinch point, and did a little work in the bowl area. My swap will be a before/after, so I'll know just what the difference was.....
 
That is interesting about the Speedmaster deal. If I won't get at least a 20 up increase by changing to Magnum heads it isn't worth the effort.
 
I just acquired a 5.9 magnum remanufactured long block and was going to switch the heads out to either the EQ or Indy but decided it wasn't worth the effort and expense going with the Hughes springs and asked them what would be the proper cam for my setup
 
toolmanmike said:
Just remember with Magnums, you will need a different intake, lifters and pushrods to make them work.
Click to expand...

.............You can have the Magnums drilled for an LA intake. "Long ago" there was a jig for that do a Google search. I was going to make one, and like everything else around here, "plans changed."
 
MOPAROFFICIAL said:
He won't find much more than the chamber diff in size if he already has 2.02 x heads.
They're 68cc he says. I know they flow at worst 218 cfm peak. Set of mags i flow tested peaked at 204-209 cfm.
How big the mag chamber in comparison might be the final blow. Probably not much diff other than shape. I'd stay with the x heads in this case. The cost/trouble to change over is close to no diff or worse.
Click to expand...

That's what I thought, but I didn't wanna stick my foot in my mouth and I knew you knew. lol
 
So it sounds like wasted effort and money to change to magnum heads? If that's the case I will probably find magnum 5.9, change cam and save up for EQ or Indy heads
 
$820 for a set of loaded aluminum heads to the door. To me that's way to close to having good work and parts into cast iron heads. From what I've seen with my own eyes as far as the SM heads vs. the amount of money, work, and time I have into my stock stuff... It's hard not to recommend sm heads...
 
Freezerman said:
So it sounds like wasted effort and money to change to magnum heads? If that's the case I will probably find magnum 5.9, change cam and save up for EQ or Indy heads
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Hope not! LOL.… I'm going to do the swap.. :) I'll say it this way, one of the best LA heads made were the 308 heads. And when they went from the LA 360 with 308's to the Mag 360, there was about a 50 hp jump, mostly do to the heads. Kegger intake was terrible for making hp.
 
Also, if you look at the MP crate motors, most of them LA's had the Mag heads. Not campaigning for anything, I just don't think it's a cut and dried /case closed that the mag heads aren't worth the swap. That's why I'm going to do it, and when I do I'll post results, as always.
 
It's not that the Magnum heads are junk. They are a good head. It's just to make them work on a LA you have to change a few things that equate to $$$$. I wouldn't replace a X or J head with a Magnum. I don't think they are that much better.
 
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I think in 318hvtwf it's going to get some gains possibly from his changing head, but the big thing is here he already has them. I mean if you have them and you just need to buy a few parts to make them work that's one thing. but to go out and spend over four or $500 on some cast-iron heads including their parts and work to put them on....
 
Sorry, just had too...… :poke: Couple of us recommended Pro Maxx on a ProComp thread, and here are the answers below......
j par said:
This is the second time you've recommended the pro Max on this Speedmaster thread.
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j par said:
I'm trying to keep this about the SM heads...
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But when somebody else ask about a Mag head on a LA, we get the pro comp recommended twice on a Mag to LA thread, read below :D
j par said:
Did you see the thread that I had on the Speedmaster heads? They have an offer right now with a free and take as well...
Click to expand...

j par said:
$820 for a set of loaded aluminum heads to the door. To me that's way to close to having good work and parts into cast iron heads. It's hard not to recommend sm heads...
Click to expand...
 
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Thanks for the advice. I would hope to gain performance. I will be watching to how it works for you 318willrun. I would have to get all the parts including intake, rockers, etc. I'm sure I could find a complete 5.9 with under 150k on it for $200 or $300.
 
Freezerman said:
Thanks for the advice. I would hope to gain performance. I will be watching to how it works for you 318willrun. I would have to get all the parts including intake, rockers, etc. I'm sure I could find a complete 5.9 with under 150k on it for $200 or $300.
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Yes, the whole motor would be ideal.
 
Freezerman said:
Thanks for the advice. I would hope to gain performance. I will be watching to how it works for you 318willrun. I would have to get all the parts including intake, rockers, etc. I'm sure I could find a complete 5.9 with under 150k on it for $200 or $300.
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Mopar! 5.9 magnum motor

Same guy has a couple pair of heads and I know him and there likely in great condition. He's a member on here and I believe has at least a set of the heads for sale on the forum. I know his name and phone number I just don't know what here on the Forum cuz I don't think he's on here much.
Maybe you might want to research why we call 318 has valves that will fly, 318 has valves that will fly....
Bahahahah....
 
318willrun said:
Sorry, just had too...… :poke: Couple of us recommended Pro Maxx on a ProComp thread, and here are the answers below......




But when somebody else ask about a Mag head on a LA, we get the pro comp recommended twice on a Mag to LA thread, read below :D
Click to expand...
Basically I'd brought up my two cents worth and had left it at that you just kind of brought it back up and regurgitated it...
Are you trying to compare$800 heads to$1, 600 heads? Because what I was trying to do was compared$400 cast iron heads that may need up to and possibly more than $200 to make them work as compared to $800 aluminum heads?
And the only reason I did say that is because I made the mistake and didn't want to see others do the same...
Again just my two cents at this money level... Bang for buck wise...
my engine builder didn't say you can slap these $800 aluminum heads on here and be good to go. I got talked into a bunch of machine work on the ones that I have...
Stupid me...
 
j par said:
Basically I'd brought up my two cents worth and had left it at that you just kind of brought it back up and regurgitated it...
Are you trying to compare$800 heads to$1, 600 heads? Because what I was trying to do was compared$400 cast iron heads that may need up to and possibly more than $200 to make them work as compared to $800 aluminum heads?
And the only reason I did say that is because I made the mistake and didn't want to see others do the same...
Again just my two cents at this money level... Bang for buck wise...
my engine builder didn't say you can slap these $800 aluminum heads on here and be good to go. I got talked into a bunch of machine work on the ones that I have...
Stupid me...
Click to expand...
I mentioned it twice, same as you here, twice. Now, back to Mag heads on LA :)
 
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