Will 3.5 EcoBoost Exhaust Manifolds Fit 3.7?

[rehoward]

I have been trying to get a definitive answer to this: Will 3.5 EcoBoost exhaust manifolds bolt to a 3.7?

So far this is what people have told me:

They will plop right on with no issues
They require a special spacer because the 3.7 exhaust bolt pattern is different than a 3.5 EB pattern
You must grind a bump off each 3.7 head so the 3.5 manifolds will fit
You can find 3.7 heads that have the same bolt pattern as the Mustang 3.7 does. This 3.7 is used on commercial trucks

I am sure there are others. So, what is the correct answer???

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[WildHorse]

Judging by pics from google.. not even close.

 

[rehoward]

Judging by pics from google.. not even close.

I just found out that the 3.5 and 3.7 use the same exhaust gasket. It has a Mustang part number. I may need to get on the phone with someone who builds the 3.7 I guess.

 

[USMCtoARMY]

I have been trying to get a definitive answer to this: Will 3.5 EcoBoost exhaust manifolds bolt to a 3.7?

So far this is what people have told me:

They will plop right on with no issues
They require a special spacer because the 3.7 exhaust bolt pattern is different than a 3.5 EB pattern
You must grind a bump off each 3.7 head so the 3.5 manifolds will fit
You can find 3.7 heads that have the same bolt pattern as the Mustang 3.7 does. This 3.7 is used on commercial trucks

I am sure there are others. So, what is the correct answer???

Read this thread : https://www.mustang6g.com/forums/threads/3-7-forced-induction.100342/

It's all there. You need adapter plates.

 

[rehoward]

Read this thread : https://www.mustang6g.com/forums/threads/3-7-forced-induction.100342/

It's all there. You need adapter plates.

I think you sent the wrong thread? That one is for a Procharger install which is a belt driven turbine supercharger. It does not use exhaust gases to work.

 

[Nagare]

I think you sent the wrong thread? That one is for a Procharger install which is a belt driven turbine supercharger. It does not use exhaust gases to work.

He said read the thread, not look at just the OP. There's a lot more information in it than just the first page.

 

[rehoward]

There is a lot of information there as well as a whole lot of Beer joint gossip. Where does it talk about 3.5 eco exhaust manifolds on a 3.7? I couldn't find anything on that. That was the whole point of my initial post. If it is in there would someone point me to the correct page please?

 

[USMCtoARMY]

There is a lot of information there as well as a whole lot of Beer joint gossip. Where does it talk about 3.5 eco exhaust manifolds on a 3.7? I couldn't find anything on that. That was the whole point of my initial post. If it is in there would someone point me to the correct page please?

Two things. ONE, I gave you an an answer. You need an adapter. Yes, people have speculated about modifying the 3.5s to fit. People buy the adapter plates from SUPERSIX or create their own. TWO, the thread mainly and specifically talks about the ECOBOOST 3.5 conversion on the 3.7L engine. Everyone of the those builds in there used an adapter kit for the exhaust manifolds. I was simply trying to infer the need to use the adapter plate, by having you read some technical work done on these platforms, but I guess our "Beer Joint gossip" wasn't what you wanted.

I think what would be beneficial would be to establish what is the purpose behind your question. I may have mistakenly assumed you were looking to boost your 3.7 with 3.5 stock ecoboost parts. Is it for another application? Do you even own a 3.7L Mustang?

FYI, I am moving to Everett/Marysville this summer if you have a 3.7 would be cool to get some drive time in the area. I am completing my Twin Turbo build while there.

 

[rehoward]

I think it would be great if we got together this summer. I would like to see your build and how you handled things and swap ideas. Yes, at some point I would like to boost the N/A 3.7 but will get the bugs out first as a stocker. And no, I do not own a 3.7 Mustang. The 3.7 motor and 6spd manual trans will be going into a 1988 Dodge Conquest.. The purpose of my question is to find ways to save money. I just cannot fathom why so many guys plunk down $4,000 for a turn key system. That is way beyond my budget and besides where is the fun in doing that? I am quite sure that you and I are from two very different generations and may see things differently. It may sound corny but one of the things I really like is sharing ideas., without being in the presence of a "hall monitor". Am I clear now?

What brings you to M'ville? That is only 7 miles from me.

PS-I do have a 1989 Fox body 5.0 convert. But that's another project :-)

 

[USMCtoARMY]

I think it would be great if we got together this summer. I would like to see your build and how you handled things and swap ideas. Yes, at some point I would like to boost the N/A 3.7 but will get the bugs out first as a stocker. And no, I do not own a 3.7 Mustang. The 3.7 motor and 6spd manual trans will be going into a 1988 Dodge Conquest.. The purpose of my question is to find ways to save money. I just cannot fathom why so many guys plunk down $4,000 for a turn key system. That is way beyond my budget and besides where is the fun in doing that? I am quite sure that you and I are from two very different generations and may see things differently. It may sound corny but one of the things I really like is sharing ideas., without being in the presence of a "hall monitor". Am I clear now?

What brings you to M'ville? That is only 7 miles from me.

PS-I do have a 1989 Fox body 5.0 convert. But that's another project :-)

I am PCS'ing there for my job in the Army. i am currently stationed in Germany. This will be my second to last move before retirement (have 19 years in the military split between the Marine Corps and Army, hence my username lol).

Super interested in the engine drop into the Conquest! One my favorite looking sports cars. With the 3.7 properly tuned and decent gear ratio that thing will be quick! I would go with a stock set of 3.7 heads. If you plan on boosting later I would go with fabricating a set of adapter plates or look for a used set from super six. The stock heads on the 3.5 would not be recommended to use on the EB conversion (serious flow restriction for our 3.7). I would look to use an aftermarket set from CRP or create a mid mount twin turbo system using an adapter flange to sync up with some shorty headers for the 3.7 (plenty of cheap stainless steel headers for the 3.7, SPEED DADDY comes to mind). Definitively willing to swap ideas and talk shop on a future turbo build or even your N/A engine swap. Even got a great custom exhaust setup for the 3.7 on the Conquest.

 

[rehoward]

Thank you for the kind words. I was casting around for a project idea when I stumbled onto the StarQuest forum. It is a great forum populated by die-hard StarQuest enthusiasts. I love the styling of the wide body version and that car looks damn fast just sitting still. I recently bought a 1988 Conquest for cheap but it is still in South Carolina waiting for me to transport it home. I think a 3.7 would be killer in the car. The 3.7 is a narrow 60 degree V so I am hoping it will drop right in. Boosted even mildly it should create something of a road/track monster. The car is a bit lighter than a 2011-2014 mustang as well. It weighs about 3,038 lbs compared to 3,401-3,601 lbs for the Mustang.

I like your idea of putting some cheap stainless shorties to work as turbo manifolds. Good flow and nice looking. I have been thinking about this for a couple of weeks as there seems to be no stock manifold for turbos except the 3.5 one, and it fastens on differently than the 3.7 manifold (similar but different bolt pattern). I think you could run the shorties exhaust outlet back and down as intended or get creative and flip the right side to the left and vice versa and then flip upside down. I think this would yield compact headers that put the turbos up front and elevated instead of down and rear facing. I think the flanges would have to be reworked a little to make this work as flipping them upside down would require a couple of new bolt locations or "tabs" welded on. Also the headers could interfere with engine accessories but it should be worth looking at anyway.

So I have big ideas but am just getting started. Right now I am information gathering and though the project sounds simple on paper, there is a lot to know up-front so all goes well during the build.

Randy

 

[USMCtoARMY]

Thank you for the kind words. I was casting around for a project idea when I stumbled onto the StarQuest forum. It is a great forum populated by die-hard StarQuest enthusiasts. I love the styling of the wide body version and that car looks damn fast just sitting still. I recently bought a 1988 Conquest for cheap but it is still in South Carolina waiting for me to transport it home. I think a 3.7 would be killer in the car. The 3.7 is a narrow 60 degree V so I am hoping it will drop right in. Boosted even mildly it should create something of a road/track monster. The car is a bit lighter than a 2011-2014 mustang as well. It weighs about 3,038 lbs compared to 3,401-3,601 lbs for the Mustang.

I like your idea of putting some cheap stainless shorties to work as turbo manifolds. Good flow and nice looking. I have been thinking about this for a couple of weeks as there seems to be no stock manifold for turbos except the 3.5 one, and it fastens on differently than the 3.7 manifold (similar but different bolt pattern). I think you could run the shorties exhaust outlet back and down as intended or get creative and flip the right side to the left and vice versa and then flip upside down. I think this would yield compact headers that put the turbos up front and elevated instead of down and rear facing. I think the flanges would have to be reworked a little to make this work as flipping them upside down would require a couple of new bolt locations or "tabs" welded on. Also the headers could interfere with engine accessories but it should be worth looking at anyway.

So I have big ideas but am just getting started. Right now I am information gathering and though the project sounds simple on paper, there is a lot to know up-front so all goes well during the build.

Randy

I am partial to the idea of using aftermarket headers and just mocking up a flange adapter for the turbos. It's obviously cheaper to do then having a custom set of headers fabricated, by a large margin...here I am talking after dropping close to 6g on my custom made top mount twin turbo setup, lol. Doing the mid mount directly after the shorty's would require a scavenger pump, which is totally not a big deal and it will work just fine, but if you were to use some stock ported or CPR aftermarket 3.5 headers what the challenge is going to be is determining the measurements to see if there is even room for a good size set of downpipes from the firewall, but I don't know the engine bay of the Conquest. Maybe it has plenty of room?

 

[SouthernCyclone]

Just have a turbo flange welded to the stock 3.7 exhaust manifold flipped on the drivers side. Use a stock passenger side 3.7 exhaust manifold and use a cross over pipe.

Exactly how my first single turbo setup was in 2015.

But I don’t understand why your not swapping in a 90-96 Mitsubishi Eclipse/Talon 4G63T with a 92 eprom ecu and use ECM link to tune with if you want a turbo engine. It’s a well documented swap for Conquest/Starion and a lot of info. Easiest to do and can make a lot of power. The aftermarket for the 4G63T is as big as a Chevy or Ford V8.

I built a 96 Eagle summit wagon awd 5 speed with Mitsubishi SOHC 4G64, forged the engine, swapped a 4G63T DOHC head with cams on it, put a 92 eprom ECU and tuned it my self for 26 psi and E85 and made 452 awhp. It weighed 3100 lbs and ran a 11.2 1/4 mile.

 

[rehoward]

Just have a turbo flange welded to the stock 3.7 exhaust manifold flipped on the drivers side. Use a stock passenger side 3.7 exhaust manifold and use a cross over pipe.

Exactly how my first single turbo setup was in 2015.

But I don’t understand why your not swapping in a 90-96 Mitsubishi Eclipse/Talon 4G63T with a 92 eprom ecu and use ECM link to tune with if you want a turbo engine. It’s a well documented swap for Conquest/Starion and a lot of info. Easiest to do and can make a lot of power. The aftermarket for the 4G63T is as big as a Chevy or Ford V8.

I built a 96 Eagle summit wagon awd 5 speed with Mitsubishi SOHC 4G64, forged the engine, swapped a 4G63T DOHC head with cams on it, put a 92 eprom ECU and tuned it my self for 26 psi and E85 and made 452 awhp. It weighed 3100 lbs and ran a 11.2 1/4 mile.

Okay, I will check it out. Is that 4G64 a six or....? 452 is a lot of moxie! Did you integrate the awd feature on the Eagle Summit wagon? Is that a turbo engine? Do these Mitsubishi engines stand boost without expensive steel components? 4G63T must be a turbo motor, right? The 3.7 is supposed to be bullet proof stock. Steel crank and rods. 6 bolt steel main caps. Hyper-eutectic pistons. Some guys have boosted it up to 600hp, stock! At least that is the story going around. You have given me something to consider. Since they are import engines maybe I could find one cheap on a Japanese salvage web site. I am actually not finding a 3.7 for cheap. Surprises me.

 

[rehoward]

Okay, I will check it out. Is that 4G64 a six or....? 452 is a lot of moxie! Did you integrate the awd feature on the Eagle Summit wagon? Is that a turbo engine? Do these Mitsubishi engines stand boost without expensive steel components? 4G63T must be a turbo motor, right? The 3.7 is supposed to be bullet proof stock. Steel crank and rods. 6 bolt steel main caps. Hyper-eutectic pistons. Some guys have boosted it up to 600hp, stock! At least that is the story going around. You have given me something to consider. Since they are import engines maybe I could find one cheap on a Japanese salvage web site. I am actually not finding a 3.7 for cheap. Surprises me.

PS - Do you have pics of your 3.7 build to share? Thanks!

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