Are 427s Reliable?
Thread Starter
Instructor
Joined: Oct 2002
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From: Fairfax Station Virginia
Are 427s Reliable?
I am considering buying a used Z06 with a 427. However, I have heard of at least one case--which was claimed not to be that unusual--of low oil pressure leading to internal engine problems. I have owned stock C5s for a number of years and never had a single problem. I am not anxious to buy a car that is much more likely to have problems--particularly ones that may be expensive to fix and not covered by a warranty.
I'd value any technical advice on the pros and cons of buying a C5 with a 427 professionally installed by a Corvette tuner. Am I far more likely to have reliability issues? Does it make a difference whether the block is a C5-R block or a resleaved LS1 block? Any other advice on upgrading to a 427 C5 will be greatly appreciated.
Doc
I'd value any technical advice on the pros and cons of buying a C5 with a 427 professionally installed by a Corvette tuner. Am I far more likely to have reliability issues? Does it make a difference whether the block is a C5-R block or a resleaved LS1 block? Any other advice on upgrading to a 427 C5 will be greatly appreciated.
Doc
Safety Car
Joined: Feb 2003
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From: Chicago il
if you are looking for reliabilty you want to stay away from any heavy midification. The 427 was designed todeliver massive amounts of power and many of the components in the motor and the drive train were not designed for it. So be prepaired for lots of maitnance. Im not saying that a 427 is an unreliable set up, lots of folks have run it with no probs. However I think that if you are moddifing a car to those extremes your gonna want to use the power.
Melting Slicks
Joined: Oct 2002
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I think all the c5's should have come with a 427, reliable and drivable depends on the setup---the 427 could be heavily built with a big cam etc and not be that street friendly but you can do the same to a 346 stock size motor, sleaving has become very reliable except for the extreme cases of a lot of added boost or nos--you can put slicks on a 346 and probably tear up your drive train, if you are not into drag racing you have no probs, things break when the tires stick on street tires that is not going to happen and you will love the 427, drive each and see which one you like, just get a reasonably tame 427 and you will see that the car was made for and really needs the extra torque and cubes, a stock c5 is not a very fast car including a zo6. If I bought a new c6 the first thing I would do is put a 4" crank assembly to go with the 4" bore and have a 402ci, moderate cam, use the 90mm setup that come on it with 1 7/8" kooks and full 3" exhaust, exedy dual clutch, hurst shifter, some brake and handling mods and you would have a great 500rwhp street car--
Burning Brakes
Joined: Oct 2002
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From: Sunny Earthquake Country, USA On the Left Coast (which is becoming more Right!)
Sounds like a good plan...
Originally Posted by NEPTUNEBILL
I think all the c5's should have come with a 427, reliable and drivable depends on the setup---the 427 could be heavily built with a big cam etc and not be that street friendly but you can do the same to a 346 stock size motor, sleaving has become very reliable except for the extreme cases of a lot of added boost or nos--you can put slicks on a 346 and probably tear up your drive train, if you are not into drag racing you have no probs, things break when the tires stick on street tires that is not going to happen and you will love the 427, drive each and see which one you like, just get a reasonably tame 427 and you will see that the car was made for and really needs the extra torque and cubes, a stock c5 is not a very fast car including a zo6. If I bought a new c6 the first thing I would do is put a 4" crank assembly to go with the 4" bore and have a 402ci, moderate cam, use the 90mm setup that come on it with 1 7/8" kooks and full 3" exhaust, exedy dual clutch, hurst shifter, some brake and handling mods and you would have a great 500rwhp street car--
Roy
Team Owner
Joined: Sep 2003
Posts: 43,084
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From: Raleigh / Rolesville NC
To my understanidng putting in a 427 ci there is more to just the engine. To do the car right, one needs to have the right clutch, drive shaft and tranny that can handle all that torque. AND suppenssion to put down to the road. maybe a chassie stiffiner too.
What good is having a 427 ci if your twisting your car all to chit and get get the power down the road??
What good is having a 427 ci if your twisting your car all to chit and get get the power down the road??
Drifting
Joined: Jul 2000
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From: the West is the best
the C5 was designed from the factory to handle horsepower. 500 RWHP in a 427 is somewhat tame compared to what many today are easily running with H/C setups, FI and NOS in astock cubed configuration. I would disagree strongly that the C5 can't put that power level to the ground.
Yes, performance increases from stock usually means assorted other upgrades(ie clutch) but a sensible approach to the goal of more horsepower doesn't necessarily equate to problems.
And for those naysayers that would still like to be pushing around in a C5 with 345 hp, wait till they see the C6 ZO6 and we will hear a crescendo of bravado from those same naysayers that today say that power level is impossible for street driving. Then and only then, will the naysayers except a 427 (and only because then it will be OEM)
Yes, performance increases from stock usually means assorted other upgrades(ie clutch) but a sensible approach to the goal of more horsepower doesn't necessarily equate to problems.
And for those naysayers that would still like to be pushing around in a C5 with 345 hp, wait till they see the C6 ZO6 and we will hear a crescendo of bravado from those same naysayers that today say that power level is impossible for street driving. Then and only then, will the naysayers except a 427 (and only because then it will be OEM)
Melting Slicks
Joined: Aug 2000
Posts: 2,900
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From: Green Cove Springs FL
Check this out: http://forums.corvetteforum.com/showthread.php?t=905590. You might want to give these guys a call to discuss if you're serious about purchasing. The block is ready to go minus heads/cam.
I think SullyC5 is a member that's had a 427 for a few years now. I can't recall many posts of having issues with the setup, normally the posts go something like: "I had fun in the vette today".
I drive an "underpowered 346", so take my advice how you wish! Good luck!
I think SullyC5 is a member that's had a 427 for a few years now. I can't recall many posts of having issues with the setup, normally the posts go something like: "I had fun in the vette today".
I drive an "underpowered 346", so take my advice how you wish! Good luck!
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The vette should have come with a 427. Night and day difference. Irronically, a 427 get less of a workout becuase of all the low speed torque, therefore casual and even moderate shift points are at least 1,000 r.p.m.'s less. Yes, there are many daily drivers.
Thread Starter
Instructor
Joined: Oct 2002
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From: Fairfax Station Virginia
Thanks to all for the comments. I do feel more comfortable in considering a 427 now. I know how to look for driveability as a daily driver, and won't be looking for anything with a race cam, etc. However, I was concerned that a tuner engine might be significantly less reliable than an OEM LS6. It sounds like as long as it is a reputable builder that has been around for awhile, and the drive train is up to the extra HP, a 427 could be a fun daily driver. Thanks.
Doc
Doc
Le Mans Master
Joined: Apr 2002
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From: Boston
Originally Posted by NEPTUNEBILL
If I bought a new c6 the first thing I would do is put a 4" crank assembly to go with the 4" bore and have a 402ci, moderate cam, use the 90mm setup that come on it with 1 7/8" kooks and full 3" exhaust, exedy dual clutch, hurst shifter, some brake and handling mods and you would have a great 500rwhp street car--
Le Mans Master
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From: Burlington ON
Cruise-In I, II, III, IV & V Veteran
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Originally Posted by ztheusa
Corvette is perfect right out of the box. The last thing it needs is a larger motor!
For the most part a well built 427+ci LS1 engine is very reliable. As long as it is built by a builder that knows what they are doing, and you have a good resleeved or c5r block, you are good to go.
The big problems come with the driveline when you try to hook the power up with sticky tires. Other than driveline problems, over the past three years of driving my c5, the only problem I have had was a broken stock rocker arm, which was a quick, inexpensive fix.
Team Owner
Joined: Jul 2003
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From: Detroit
Originally Posted by ztheusa
Corvette is perfect right out of the box. The last thing it needs is a larger motor!
Mark
Last edited by mdhmi; Sep 19, 2004 at 11:04 AM.
Melting Slicks
Joined: Oct 2002
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By time I would get around to it I'm sure the software etc would be available, I am in no hurry to **** away more money on a new project this one has been a big enough pain, besides if I upgraded to a new project car I would deff wait and see what the new c6 zo6 has to offer, and maybe not even touch it with the possible exception of some header/exhaust and air intake mods to let it breath better--