swap in Cobra long block with Eaton?

chief455

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is swapping in a complete Cobra 4.6 pretty straight forward, needing some external parts changed to fit Marauder?

looking at this to gain forged internals/stronger block while adding a blower to the Marauder.
Power/boost level should be significantly higher this way, yes?
Pros?
Cons?
 

musclemerc

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Block swap is no problem. The cobra block is 90LBS heavier than the aluminum stocker. Personally I would go for a built motor with an aluminum block and swap your heads onto it. JDM engineering has pretty good pricing.
 

daturbosix

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all to save 90lbs off a 4200lb car? ha.. not worth it IMO
 

chief455

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MOTOWN

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For an Eaton swap i would rather have the 10.1 comp motor versus the 8.5 comp iron block motor, the 10.1 setup will give you a ton more torque on the street!

If you want a forged motor build a 10.1 aluminum 4.6l and enjoy your Eaton.
 

Zack

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For an Eaton swap i would rather have the 10.1 comp motor versus the 8.5 comp iron block motor, the 10.1 setup will give you a ton more torque on the street!

If you want a forged motor build a 10.1 aluminum 4.6l and enjoy your Eaton.

I disagree.
8.5:1 is way to go. And torque does not suffer at all..And you can beat the shit out of the car without risk of detonation.
 

MOTOWN

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I disagree.
8.5:1 is way to go. And torque does not suffer at all..And you can beat the shit out of the car without risk of detonation.
The only reason torque won't suffer is because of the Eaton and so much low end torque, at 10.1 detonation wouldn't be a problem unless some bad 93 octane got in the mix
 

Zack

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The only reason torque won't suffer is because of the Eaton and so much low end torque, at 10.1 detonation wouldn't be a problem unless some bad 93 octane got in the mix
Its a horrible problem constantly, have you ever owned an eaton swap car with 10:1?
You cant run more than 12-13 degrees of timing and heat soaking pulls even more timing.

And the detonation isn't always at WOT. A lot of it is at part throttle in 3rd or 4th gear.
 

MOTOWN

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Its a horrible problem constantly, have you ever owned an eaton swap car with 10:1?
You cant run more than 12-13 degrees of timing and heat soaking pulls even more timing.

And the detonation isn't always at WOT. A lot of it is at part throttle in 3rd or 4th gear.
Nope never owned one, but swaped two for friends detonation was only a problem for them when they went below 93 octane, comes with owning a 10.1 4200+ lb car! Lol
 

Zack

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The point im trying to make is simple:
You leave zero margin for error on a shortblock that is fundamentally weak from the get-go.

8.5:1 and positive displacement (with 93 octane) FTW
 

MOTOWN

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The point im trying to make is simple:
You leave zero margin for error on a shortblock that is fundamentally weak from the get-go.

8.5:1 and positive displacement (with 93 octane) FTW
I completely understand your position on the comp issue, i just dont agree with it thats all, if you firmly believe in 8.5.1 comp w/Eaton blowers thats cool.

I my self would go 10.1 as i have many times in the past.
 

chief455

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thanks for airing compression ratio preferences, but I just want to know what fully forged shortblock will swap into my Marauder?
It seems a Cobra 4.6 is good candidate, just iron block weight and an 8 bolt flexplate needed?
Since I decided to boost the car, I'm going to build from the bottom up. I've learned my addiction problem, and am at one with it ;)
I have suffered the 'tuned for your compression/octane' detonation blues, and rebuilt the damaged motor with less compression for safety margin. On a street car, that is much more important than a high power number to me.
Heck, after 450rwhp, it's all too much for the street anyway!
 

musclemerc

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I agree 450HP is fun on the street. The best thing about modding a Marauder is we drive a rare breed. Having boost is just more icing on the cake.

Be sure to start a thread when you start turning wrenches
 

chief455

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I agree 450HP is fun on the street. The best thing about modding a Marauder is we drive a rare breed. Having boost is just more icing on the cake.

Be sure to start a thread when you start turning wrenches
WILL DO.
I'M ON THE FENCE ABOUT USING MY STOCK MM ENGINE NOW, SEVERAL GUYS ARE INTO 12'S WITH THEM, JUST EATON, OTHERWISE STOCK - THAT WOULD BE LOWEST COST FUN FACTOR..sorry, caps lock
 

musclemerc

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What's wrong with your stock engine? I SC'ed mine after 100,000mi without any worries. I always fixed any mechanical issues and it's never ran hot.
 

chief455

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What's wrong with your stock engine? I SC'ed mine after 100,000mi without any worries. I always fixed any mechanical issues and it's never ran hot.
nothing - healthy 82,000 mile car with rebuild trans and 4.10

I had a expensive detonation from going lean happen on a different car, showed me 2 seconds of low fuel supply hammers the pistons dead, and it snowballs from there.:roflpicard:
I'm paranoid, period.
After reading Lidio's 2003 success with Trilogy and over 10lb boost, and other current members getting 12's out of stock motors with Eaton only - I'm leaning back toward using my engine as is.
Scary for me is tuning - after the install, how do I run the car on my current N/A tune? trailer it to a dyno tuner?
 

Zack

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An eaton swap with 10psi and no headers makes for a really fun car.
There is not a big 'seat of the pants' difference between 420rwhp and 475rwhp.
 

chief455

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An eaton swap with 10psi and no headers makes for a really fun car.
There is not a big 'seat of the pants' difference between 420rwhp and 475rwhp.
bingo.
My Procharged T/A dynoed 580rwhp by previous owner, and though fast, it never felt right, and detonated.
Since full rebuild, dyno tuned conservative 500rwhp = ridiculous tire buning machine with zero scary timing in my brain.
 

musclemerc

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nothing - healthy 82,000 mile car with rebuild trans and 4.10

I had a expensive detonation from going lean happen on a different car, showed me 2 seconds of low fuel supply hammers the pistons dead, and it snowballs from there.:roflpicard:
I'm paranoid, period.
After reading Lidio's 2003 success with Trilogy and over 10lb boost, and other current members getting 12's out of stock motors with Eaton only - I'm leaning back toward using my engine as is.
Scary for me is tuning - after the install, how do I run the car on my current N/A tune? trailer it to a dyno tuner?
Run it like it is. I don't think you will have any issues with your current milage. Just remember to not go any bigger then a 3.0 pully on the Eaton you got. Any more than 13lbs of boost and all bets are off on your stock block.
 

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