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03-04 Cobra education time


BrianZ06

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To make a long story short I sold my WS6 to get into a C5 Z06. My plan was to buy an already done heads/cam Z06. My 2nd plan if I could not find a well built modded one was to buy a stocker and do the cam upgrade with a set of headers,etc,etc. They are a simple and very reliable car that handle and perform well with or without upgrades that is why I like them. After seeing some 03-04 cobra's making crazy power I must say they have my attention buy I don't know a whole lot about them and what to look for when buying one. The common problems and the maintenance is what I need info on from you guys that own these. Both cars are in about the same price range depending on what has been done to them. Most of the cobras have had pulley swaps and other thing done to them. Are the bottom end of these engines strong enough to hold that much power ? What about the stock tranny and rear differentials.
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To make a long story short I sold my WS6 to get into a C5 Z06. My plan was to buy an already done heads/cam Z06. My 2nd plan if I could not find a well built modded one was to buy a stocker and do the cam upgrade with a set of headers,etc,etc. They are a simple and very reliable car that handle and perform well with or without upgrades that is why I like them. After seeing some 03-04 cobra's making crazy power I must say they have my attention buy I don't know a whole lot about them and what to look for when buying one. The common problems and the maintenance is what I need info on from you guys that own these. Both cars are in about the same price range depending on what has been done to them. Most of the cobras have had pulley swaps and other thing done to them. Are the bottom end of these engines strong enough to hold that much power ? What about the stock tranny and rear differentials.

 

As far as the bottom ends, they are well built from the factory. They came with forged pistons, good crank, and manley rods. As long as you have a good tune and enough fuel, these bottom ends have seen 800+ rwhp. They won't last forever at that power, but it's very possible. A good safe tune and 550-600 rwhp will last awhile as long as you don't do too many back to back top end pulls. The rear diff is a 31-spline unit that is relatively strong, but with the IRS and wheel hop that can create issues with the stock half-shafts. If you beat on the car, powershifting and things like that, it's a toss up with the stock transmission. It has a 10-spline input shaft, which isn't the best for these cars. I'm sure all of the other guys will chime in and add to this, so this is all I have for now.

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I am bias to Corvettes, like Dave maybe to 03-04's.

 

The thing that mostly drives me towards the vette is overall driving performance, I believe the vette is a little more tuned for corning, and overall feel, with a little less brute power then the cobras. The corba is a little heavy of a car for my liking, but again thats my bias. I work around both, and they do differnt tasks well.

 

I would say the vette, for overall performance, and you can make 440 wheel easily, and Ill bet that hangs with all the 500 wheel 03-04s out there. ;)

 

-Brandon

(and good luck, if you want to take a ride in a vette with around those levels of power stop down at the shop and we would be obliged to set you up with a demo ride)

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I am bias to Corvettes, like Dave maybe to 03-04's.

 

The thing that mostly drives me towards the vette is overall driving performance, I believe the vette is a little more tuned for corning, and overall feel, with a little less brute power then the cobras. The corba is a little heavy of a car for my liking, but again thats my bias. I work around both, and they do differnt tasks well.

 

I would say the vette, for overall performance, and you can make 440 wheel easily, and Ill bet that hangs with all the 500 wheel 03-04s out there. ;)

 

-Brandon

(and good luck, if you want to take a ride in a vette with around those levels of power stop down at the shop and we would be obliged to set you up with a demo ride)

 

I'm not really biased. I like them both. If I could have both I would. I think you hit it on the head with the Corvette being the better overall performer here. I still really like my car, but I definitely would drive a ZO6. Lighter and better handling. The weight and aero play a big role in the lower powered vettes hanging with the higher powered Cobras. Either one works well.

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Thats some good info. I knew the engines were forged but I did not know what parts they used for the build. I might take you guys up on the test drive offers. Hal I will be giving you a call. I am sure you know these cars inside and out. The vette is what I am leaning towards. I found a couple of vettes I might be talking to you guys about.
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modularfords.com is your friend, as is svtperformance.com

 

these things can handle 600rwhp all day long, and be dead reliable. i've had the bigger blower on my car for almost 3 years with zero issues--zero. i have the stock tranny, stock clutch, and virtually stock rearend--just springs, an IRS brace, and subframes. honestly can't believe that the stock clutch has lived at nearly 600rwhp for almost 3 years.

 

if you want to be serious about launching at the strip, then you'll need to upgrade the IRS, or go solid rear. you'll also have to add an aftermarket clutch, and tranny input shaft. but the bottom end is strong enough to let you go deep into the 10's

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Thats some good info. I knew the engines were forged but I did not know what parts they used for the build. .

 

forged steel crank

forged manley rods

forged pistons

iron block

 

only weak point in the bottom end are the pistons are just a bit too big for the bores to prevent piston slap with cold starts----high heat (back to back 40-140 highway roll races) will cause the pistons to expand and score the bores.

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When looking at an 03/04 Cobra, make sure you check the rear diff as they tend to leak at any mileage. Also make sure the engine doesn't have any head tick if its an 03, a lot of guys have had them replaced under warranty with revised 05 heads. It would be nice if the car already has the cooling mod done.
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i should be at the cr car show tomorrow some time if you want to ride in my car.

 

for the cost to mod with something to live a long time its hard to beat a lsx engine. or the drivetrain for that matter in a vette.

 

insurance is another thing to keep in mind. i know my vette is cheeper than the mustang i had. out of the 3 cars me and ashley have (cts-v, tbss and the z) the vette is the cheepest of the 3.

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these things can handle 600rwhp all day long, and be dead reliable. i've had the bigger blower on my car for almost 3 years with zero issues--zero. i have the stock tranny, stock clutch, and virtually stock rearend--just springs, an IRS brace, and subframes. honestly can't believe that the stock clutch has lived at nearly 600rwhp for almost 3 years.

 

I second that. 3 years running between 550-600RWHP with zero issues. Completely stock except for the blower/injectors and MAF.

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Sounds like the cobra will handle the power just as good as the Z06.I have been reading a lot of info on the cobra. I like them but the Z06 is more of what I'm looking for at this time and to make the decision easier the wife is telling me the vette is what she wants me to get. I'm like ok. She likes the looks of them better. Cant argue with someone who contributes to half the income. She never wanted to drive my stalled 400 rwhp WS6. She will drive the vette.

AJ thanks for the offer I had to many things to do today around the house today . First saturday off in a long time.Work has been very busy so far this year. I'm one of the few that can say I have a lot of work to do in this rotten economy.

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Sounds like the cobra will handle the power just as good as the Z06.

 

cobra can handle more power than the vette, and make it much easier and cheaper (assuming you don't just throw a 200 shot at the vette)

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To make a long story short I sold my WS6 to get into a C5 Z06. My plan was to buy an already done heads/cam Z06. My 2nd plan if I could not find a well built modded one was to buy a stocker and do the cam upgrade with a set of headers,etc,etc. They are a simple and very reliable car that handle and perform well with or without upgrades that is why I like them. After seeing some 03-04 cobra's making crazy power I must say they have my attention buy I don't know a whole lot about them and what to look for when buying one. The common problems and the maintenance is what I need info on from you guys that own these. Both cars are in about the same price range depending on what has been done to them. Most of the cobras have had pulley swaps and other thing done to them. Are the bottom end of these engines strong enough to hold that much power ? What about the stock tranny and rear differentials.

 

They are ranked one of the most UNreliable actually. Maybe thats the C6....either way, not real reliable. (From what i have heard from my gf's dad who has a collection of them)

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They are ranked one of the most UNreliable actually. Maybe thats the C6....either way, not real reliable. (From what i have heard from my gf's dad who has a collection of them)

 

Where did you ever hear that ? One of my customers has over 100,000 miles on his vette with no problems and it looks great.

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