SpeedMaster Heads for a 5.9 Magnum

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@MOPAROFFICIAL

Hi, i have read this thread but not quite sure if I understand everything correctly. I want to buy these Speedmaster heads: Mopar Chrysler SB 318 360 170cc 65cc Hydraulic Roller Assembled Cylinder Heads
My cam is Comp cams 20-746-9.

Are these heads p&p for Mag engine with factory rocker arms or Kegger intake manifold or do they need mods/parts to bolt? If so can you list them to me if it's is not a problem for You?
Also can I expect around 300HP to the crank with this setup. I already did Kegger mods.
sorry form my poor English but I'm internal, Poland in Europe.
best regards
WASyL
 
Magnum engine you have, these will work if you have an early magnum block that had the oil passage drilled to feed the rockers.or have it drilled . iIRC there were other small things that need to be addressed.
 
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If you use these heads on a Magnum block, IE a block that has no provisions for oiling p through the block into the cylinder head, you’ll need to make sure you use an AMC lifter or just simply a pushrod oiling lifter, hollow pushrods and a rocker that will oil from the pushrods.
 
You cannot put the magnum rockers on the heads you linked. Magnum rockers are pedestal mount, those heads use shaft rockers. You can't use magnum intakes either, the bolt angles are different.
 
Yellow Duster said:
You cannot put the magnum rockers on the heads you linked. Magnum rockers are pedestal mount, those heads use shaft rockers. You can't use magnum intakes either, the bolt angles are different.
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Thanks, that's very important for me.
Are there any cheaper then Edelbrock or Trick flow heads that will bolt with stock Magnum intake ?
 
These ones?
https://hughesengines.com/Index/pro...HM=&searchmode=partnumber&page=1&partid=35599

With this price range for cast iron I'd rather rebuild my stock "prone to crack" ones. I'm was wondering are there any aluminium ones in that price range even if flow numbers would be worse then TF or Edel but better then stock.
I'm not trying to be cheap, but shipping and taxes will at least double the price for me :-(
 
Yea man! It’s a heavy price to pay. There is another fella from Poland here. I can’t remember his screen name but he plays with big blocks and has a couple of honestly really cool and bad *** engines.

Edelbrock is the only maker of new “Magnum” heads.
Trickflow has a head that will work on the Magnum block but only uses the LA intake bolt pattern. There are specific rockers to use, Harlandsharp is the company.

For EZ, and run the edelbrock head for use with the Magnum style intake.
 
Do Promaxx flow any better then stock ones or not prone to cracking ?
 
WASyL said:
Do Promaxx flow any better then stock ones or not prone to cracking ?
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Rumble, I'm looking for heads for my magnum, I looked at the promaxx, you said, they are a copy of the 671 head, non performance
I'm thinking you meant the promaxx 723-93605
 
WASyL said:
Do Promaxx flow any better then stock ones or not prone to cracking ?
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I linked the stock replacement heads bare and loaded from Promaxx. Also a link to Hughes engines for there stock replacement head. The last link is the Edelbrock head which flows a good bit more than stock.
The listed stock replacement heads did not have any flow rates listed with them.
Brooks James said:
Rumble, I'm looking for heads for my magnum, I looked at the promaxx, you said, they are a copy of the 671 head, non performance
I'm thinking you meant the promaxx 723-93605
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Hey Brook. I said nothing of the sort. I looked back and can not find it so quickly. Even worse since the thread started in ‘21.
Can you post a better link. That one just keeps saying to me - dial this number?

The promaxx I linked is the Alabama guys. Nice work from them.

As far as what the head is exactly, I don’t know if it is a copy, recast, new casting, upgraded casting. Off hand, I don’t remember reading such a thing anywhere.
 
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