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Discussion Starter #1
I've got a question for those who know about the blocks used in the modular family. I must admit that I'm not too knowledgeable technically speaking when it comes to engines so please give me some slack. First of all a 5.4L should have a bigger block than a 4.6L right? A bigger crank needs a bigger home to spin in???? But if this is true how can you buy stroker kits for existing engines, surely part of these kits is not a replacement block?!!!? So then are the alloy blocks from a 4.6L Mustang Cobra interchangeable with the iron blocks from a 5.4L Boss. Surely that can't be possible but it's a burning question for me!!!! Just how much weight can be saved with an alloy block in a 5.4 L engine, does anyone know? I believe that with the two cars being so close now in terms of size that this must the main area where Commodores are picking up their weight advantage over Falcons. And what, besides from cost, are the disadvantages of using an alloy block??? I've heard iron is stronger &, more importantly, consistently stronger, and also quieter than alloy in terms of unwanted engine noise. Maybe, BUT IT'S ALSO A SH*^-LOAD HEAVIER!!!!! Could someone who knows fill me in!!! Why in the hell are Falcons giving so much lost performance away for the sake of an iron block.
 

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DOHC 5.4 Racer
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110 Posts
The 5.4 has a 29mm taller deck to accomidate the longer (4.165'') stroke. (Like the diff. between a 302/351 windsor)It is not possible to put more than 3.75'' of stroke in a 4.6 block.
The Aluminum 4.6 block weighs 89 pounds, Iron 4.6 158 pounds, Iron 5.4 183 pounds
 

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Two SC 61's = trouble
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6,360 Posts
Just to compare weights my DART 302 block is 160 Lp..

I see Ford used the Iron block for its S/C[ Lightning] motors..Unless its changed lately...
 

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BSR Twin System (tm)
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4,751 Posts
I think the new FORD GT (aka GT-40) uses an Aluminium 5.4 Block.
 

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Discussion Starter #6
Thanks for the replies. Looking at the weight differences between the 4.6L iron & alloy engines it looks like there's potentially a very significant weight saving if Ford was to go down that path with the 5.4L. So how about it Ford Australia! I still have yet to hear any REAL disadvantages with alloy blocks. From what I know the Ford GT does use an alloy block but I have heard that you can order a alloy 5.4L block through the Ford Racing catalogue from the U.S.A. Perhaps our American friend could shed some light on this one? And now for my dumb question.......... What's deck height???
Is this the distance from the centre of the crank to the top of the block/bottom of the head? Or is it just the distance from top to bottom, vertically speaking, for the block?
 

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Aussie Ford Fan
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I did read on Blue Oval News a year or so ago that sometime in the future all modular blocks will be produced in alloy
 

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I take it when people talk about an engine block being made of alloy, they mean an aluminium alloy? Because you could have a 99%iron alloy??!!

Don't the 4.6 and 5.4 share the same block? Like you could take a 4.6, and stroke it to 5.4L which is the same thing as a 5.4 out of the factory Please correct me if I am wrong

So even truck Modular "Triton" engines will be have cast aluminium blocks? I wonder if it will be tough enough for that purpose?
 

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BSR Twin System (tm)
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chevypower said:
I take it when people talk about an engine block being made of alloy, they mean an aluminium alloy? Because you could have a 99%iron alloy??!!

Don't the 4.6 and 5.4 share the same block? Like you could take a 4.6, and stroke it to 5.4L which is the same thing as a 5.4 out of the factory Please correct me if I am wrong

So even truck Modular "Triton" engines will be have cast aluminium blocks? I wonder if it will be tough enough for that purpose?
The 5.4 has a taller Block than the 4.6 to allow for the longer stroke.
 

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DOHC 5.4 Racer
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110 Posts
The the deck height is 29mm taller on a 5.4...Think of it like 302 to 351...Same design except for stroke, rod length,deck. As such the 4.6/5.4 does not use the same block.
 
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