How reliable is this engine, I understand you have to get a 6 liter block, but my roommate thinks it will be very unreliable. Is he right? or will a 402/408 be just fine if its installed right.

 

unreliable in what way?

should run for a long time. like 100+k miles i would think.

 

A 408 should be a lot stronger with a forged crank,stronger rods and forged pistons.If it's assembled right,it will last a long time.

 

not necesarily the motor, but other parts as well. The reason I ask, is because he thinks it will be in the shop every other week if I did a 408/402, mainly because (as Todd@ProDyno knows), there is a Trans Am with a 402 in it at Pro Dyno thats in all the time and seems to be in quite often because something is always being worked on with it. I don't really know all the details, but I thought a 408/402 was supposed to be reliable, street driveable power.

 

inevitably if you build an extremely strong engine and don't upgrade your trans and 3rd, you're going to break them both, which might be the mentioned trans-am's problem, and the only weak link in a 40X daily driver. i would also expect a 40X to last 100k+ miles when built properly.

 

so basically if I got a worked tranny and stronger rear-end, I would be ready to do a 40X reliably.................

 

exactly. it would be a bad suprise to blow lots of money on a nice 408, only to shell the trans shortly after installing it. unless you think you could actually stay out of the go pedal until the trans and 3rd are done (i couldn't) then prepping them first would be a better plan.

 

yeah thats what I was thinking.


what do you mean when you say 3rd??

 

yeah i know my bro has a 408 and it runs like a champ the only thing he has had to fix since then was his tranny and this is his third motor with over 500whp and it lasted him about a year driving it real hard the truck runs like a scalded cheetah now.

 

There are a TON of things to consider when determining reliablility, and cubic inch displacement really isn't one of them. Compression ratio, cam size, RPM operating range, tuning (as far as A/F and detonation are concerned) etc, are some of the things that factor in when trying to determine engine life. A 4.8, 5.3, 6.0, or 408 with the same specs (other than bore and stroke size of course)should have the same life span as each other. I don't see where the difference would be just because it displaces 408 CI. Keep in mind also that GM is "rumoured" to be putting a 427CI LS2 in the new Z06 (or Z07 whatever they decide to call it) when it comes out in 2006. They are said to debut the car at the Los Angelos auto international auto show. I'm sure they didn't engineer this motor without thinking about longevity and reliability to some extent.