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Discussion Starter · #1 ·
What’s up everyone. So I have the option to build either a cast iron from an 07 Shelby or an aluminum from a 12. I already have the rotating assembly and the complete engines. In addition I have a set of low mileage 13/14 cams that at minimum would use. ( I would like to keep low key power for now ). I’m sure once built things could change, but at the moment that’s my plan.
Im just seeking input as to the cost vs benefits of building either one. Also are the heads any different between years? Or are they the same? I’m not considering any porting at the time. Thanks everyone
 

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Discussion Starter · #3 ·
I agree with you on sleeving it, but is it really necessary? If nothing is wrong with it, only being pulled and built to have the peace of mind. These engines make soo much power easily. With minimal bolt ons and a great tune, they can easily eclipse the 800 HP mark and reach the limits on the rods.
 

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it would be your call.
the alloy blocks only have plasma bores, and the plasma isn't that thick.. i am not sure on ring seal success even after a light hone for new rings.
i have read about success going both ways. maybe others can comment on that.
i try to live by the motto of do the job right the first time. it's usually cheaper in the long run.
 

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Discussion Starter · #5 ·
Thanks! That’s what I was looking for. I didn’t know if you could just do a regular hone, along with a line bore on a build, which is more common with the cast iron blocks.
So to be clear…It’s best practice to sleeve the aluminum block. I’m not looking to make 1000 hp, but mid 8’s to low 9’s seems easily attainable with mild bolt ons so I was thinking just to replace the weak ass rods and leave everything else stock, so I could have reliable HP.
 

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With the aluminum block, a lot depends on the mileage and how much plasma liner you have to work with. New rings need a rough surface to seat and honing the plasma liner could be a tricky endeavor with some amount of wear in a cylinder. Safe bet is to go with sleeves. I would think the iron block will devalue the car when you go to sell it.
 

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Discussion Starter · #7 ·
Well… up to this point I haven’t mentioned that the built engine would be on my Shelby. I’m planning on building the engine on my 94 cobra with an 07 Shelby 5.4. I have worked out most of the bugs from the swap and I’m feeling ready to finally build it and make power. Currently it’s on a 2.5 upper and JLT cold air, tune running the returnless fuel system but it’s capable of being converted to a full return system with 3 fuel pumps if needed. I got a fair deal on a complete 12’ long block including the trinity blower that was modded on e85 making 730 at the wheels. I could just tear it down and have it built, or… swap it out and have the 07 built. The light sn95 chassis compared to the heavier s197 makes a big difference on the track. So I really don’t want to make too much more than high 800’s if that. So devaluation of the car is not something I’m worried about. I just want reliability and confidence.
I am seriously considering just sleeving the block anyway. But what I’m really looking for is which of the two blocks is better to build. Thank you
 

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The aluminum block was built with more substantial webbing. The iron block is the same block used since 1997 in millions of gas powered trucks, including the Lightning, and there wasn't a beefed up version for the GT500. Builders say it's good for 1,000 hp, the aluminum 1,200 hp. When Ford built the GT in 2005, they developed an aluminum block for it with sleeves. If you're going to flog it at the track, I'd do the aluminum block. Just make sure you get someone that knows what they're doing to install the sleeves.
 

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The first question to ask is how much power do you realistically want to make. The further you're below the max power threshold of your short block's max Hp, the longer it could last. Timing components not withstanding, they are always a gamble with big Hp cars.

On the other side of that, I've blown up a half dozen motors that were all built "the right way" so it's always a gamble. :)
 

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Discussion Starter · #10 ·
Thank you both for the replies!!
@ Catmonkey, that’s the answer I was looking for!! So it looks like I’ll be doing a sleeved aluminum block!
now @ Wolvee, I’m not looking to make more than 850/890 on e85.
realistically I’ll be bumping compression by .5 from stock and maybe just doing a stage 1 port job from Modular Head Shop, possibly use the stock 13/14 cams and a VMP Gen 2 or the 13/14 trinity blower, 1300 injectors and full return system. Realistically that should put me in the low 800’s if that ( depending on how much boost). But at that point I won’t be afraid to turn it up if I feel like it.
I don’t believe that I’ll be doing aftermarket cams. I want it to sound like stock. It’s not a purpose built car other than an occasional drag. Otherwise it’s a full on street car with working A/C, heat and nice stereo.
please keep the input going!! It’s very much appreciated!!
 

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I don't think the 13/14 cams would work in the 07 block.
 

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Discussion Starter · #12 ·
I don't think the 13/14 cams would work in the 07 block.
I think you’re partially right…not sure yet, I would have to do real research but I was understanding that these where same at Ford GT, and therefore I also needed the springs that match. I’ll have to contact MHS and ask about it since the heads will be going there also.
 

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I don't think the 13/14 cams would work in the 07 block.
Sure they will. All modular DOHC without VCT are interchangable. It's just whether the cam specs can work with your combination. 5.4/5.8 are "down in the hole" for piston to valve clearance so even radical cams are likely to fit without valve reliefs on factory style pistons. There are a lot differences in valve springs between engines. However, the same valve springs were used on all year GT500s.

I think you’re partially right…not sure yet, I would have to do real research but I was understanding that these where same at Ford GT, and therefore I also needed the springs that match. I’ll have to contact MHS and ask about it since the heads will be going there also.
Same springs as the 07-12 were used in the 13-14.
 

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Discussion Starter · #14 ·
Sure they will. All modular DOHC without VCT are interchangable. It's just whether the cam specs can work with your combination. 5.4/5.8 are "down in the hole" for piston to valve clearance so even radical cams are likely to fit without valve reliefs on factory style pistons. There are a lot differences in valve springs between engines. However, the same valve springs were used on all year GT500s.


Same springs as the 07-12 were used in the 13-14.
Thank you for clarifying that!
The truth is that is what I was hoping to find out. I haven’t had any time to do any research on the build, since I’m not really in a hurry. I really need to plan everything out down to the last cent, because I would like to do it on my 5.8 also. Speaking of which, I found someone selling a bare 5.8 with the main caps for $4500. It appears that he built a new one and had this one leftover.
what is a fair price to pay for one?
 

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Is the 5.8 new? If not, you have a similar issue to the 5.4 and the thickness of the plasma liner. You know if you sleeved the 5.4, you can bore it out to the 5.8 bore diameter? If I'm not mistaken all the sleeves are 5.4 standard bore. You can bore it out from there to whatever piston diameter you have to fit it. I've seen new 5.8 bare blocks priced between $4,000-$6,000. Just depends on supply and demand. I'm sure Ford has discontinued production on these and when you're going, they're gone. Tasca shows current pricing at $4,494, so they appear to still be available through the dealer network, but you'd need to check availability.
 

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Discussion Starter · #16 ·
Is the 5.8 new? If not, you have a similar issue to the 5.4 and the thickness of the plasma liner. You know if you sleeved the 5.4, you can bore it out to the 5.8 bore diameter? If I'm not mistaken all the sleeves are 5.4 standard bore. You can bore it out from there to whatever piston diameter you have to fit it. I've seen new 5.8 bare blocks priced between $4,000-$6,000. Just depends on supply and demand. I'm sure Ford has discontinued production on these and when you're going, they're gone. Tasca shows current pricing at $4,494, so they appear to still be available through the dealer network, but you'd need to check availability.
Wow!! Thank you!!
 

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Discussion Starter · #17 ·
@Catmonkey , do you know if the rotating assembly is the same as the 5.4? Besides the pistons?
In other words, can I use the same crank and New Rods as the 5.4 ?
Thanks!
 

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Cranks are all the same. There is a difference in the rod and piston. First off you're dealing with different bore sizes for the pistons, but a change in the piston crown on the 13-14 cause a taper to be machined in the small end of the connecting rod. Most aftermarket pistons aren't configured as such, which allows you to use a standard 5.4 connecting rod, which all the aftermarket rods conform with. JDM has Manley rods machined for the taper as they use the factory Mahle pistons in their 5.8 builds. If you wanted to use stock 5.8 pistons, you'd need to get a set. I've got Manley pistons in my 5.8 along with their I-beam rods, with a standard GT500 crank.

The 5.8 block has another set of steam holes that send coolant into an extra passage in the cylinder head between the exhaust valves. Using 5.4 heats on a 5.8 block just terminate the steam hole at the head. You would need to use 5.8 head gaskets with a 5.8 block. Also the 5.8 block has piston squirters. I plugged all my piston squirter holes. You don't really need them with good quality pistons and it's just another source for a bleed down of oil pressure and additional crank windage.
 

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Discussion Starter · #19 ·
Cranks are all the same. There is a difference in the rod and piston. First off you're dealing with different bore sizes for the pistons, but a change in the piston crown on the 13-14 cause a taper to be machined in the small end of the connecting rod. Most aftermarket pistons aren't configured as such, which allows you to use a standard 5.4 connecting rod, which all the aftermarket rods conform with. JDM has Manley rods machined for the taper as they use the factory Mahle pistons in their 5.8 builds. If you wanted to use stock 5.8 pistons, you'd need to get a set. I've got Manley pistons in my 5.8 along with their I-beam rods, with a standard GT500 crank.

The 5.8 block has another set of steam holes that send coolant into an extra passage in the cylinder head between the exhaust valves. Using 5.4 heats on a 5.8 block just terminate the steam hole at the head. You would need to use 5.8 head gaskets with a 5.8 block. Also the 5.8 block has piston squirters. I plugged all my piston squirter holes. You don't really need them with good quality pistons and it's just another source for a bleed down of oil pressure and additional crank windage.
So does that mean I can or can’t use the 5.4 aluminum block to make a 5.8? If I’m understanding correctly, the 5.8 block has differences between the 5.4 which seem like improvements. I have two perfectly running 5.4’s at this time, one being the 07 cast iron and the other from a 12. I was considering getting a brand new or used aluminum block and building that one to replace the cast iron block, but using the rest of the components to put it back together. The iron block only has 14k and the aluminum has 47k. This is great information. Thank you
 

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You absolutely can build an engine with or without the steam holes. You just won't have that passage if you use any 5.4 components. We're talking about a 1/16" steam hole. Ford came up with it in their long-term durability testing, the extremes of which your engine is not likely to ever see. The 5.4 and every other DOHC modular gets along fine without it. I've been running the 5.8 block and without the steam holes in my 5.4 cylinder heads for 8 years. It's just not an issue and I monitor my cylinder head temperatures. If you think that steam hole is important you need a 5.8 block and 5.8 heads. That's not to say there isn't some machinist out there that couldn't add them to a 5.4.

Here's what they look like, note the circle on no. 3.

Automotive engine gasket Automotive lighting Gas Audio equipment Machine


The passage in the cylinder head is much smaller.
 
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