3400 swap questions

[AM6_Cutlass]

Those of you that have been following my thread in the general discussion area know that my 3100 has a bad head gasket or bad head, and the estimate is $1500. I've also come to the conclusion that my car is pretty much worthless as a trade in its current condition, and I haven't found an immediate suitable replacement.

 

So, I'm looking into the possibility of having the engine swapped for a 3400 since I don't want to spend anything on either fixing or replacing my 3100, and a 3800 will require a new tranny as well. I managed to find a 3400 out of a 2002 Impala listed on a local salvage yard website. The engine has 2k miles on it (they had about a dozen 2000-2002 3400s listed, but they were all the same price so I'd go with the lowest mileage one obviously). I just need to find a place to install it now. Anyway, is there anything else I need/need to know? Can I use my current tranny without any problems? Do I need a new computer or to get mine reprogrammed? Anything else I'm missing?

 

Thanks in advance guys...

[Robby1870]

yeah Im pretty sure 3100 and 3400 are the same block since you can put 3400 heads on a 3100 or even a 3.1L. It should work. Just make sure to get the computer with the engine and any and all accessories that you can. Sounds like fun, have fun with it and enjoy the extra HP.

 

Robby

[Guest]

I think he is talking about the entire engine though, not just a top end and head swap, but the WHOLE thing.

[Robby1870]

yeah I know, I mentioned the blocks to let him know his tranny would work with the 3400.

 

Robby

[AM6_Cutlass]

Thanks guys... yes, I am talking about swapping the entire engine. It is good to know that they are the same block, that means the engine mounts should be the same as well as the overall size. I didn't know that had any relation to the tranny (with all the electronic programing I didn't know there if there were differences in shift points or whatever to take advantage of the different hp and torque between the engines). Good to know. Is this pretty much a direct swap then, as in no harder than just replacing with another 3100?

[GnatGoSplat]

I think you can just swap the whole thing.

This is just a guess, but since your 96 3100 was MAF, your PCM shouldn't have a problem with the 3400. I don't know if the injectors are bigger on the 3400, but if they are, you would want to make sure to use those.

This should be a direct swap. They are virtually identical engines except for bore.

[Robby1870]

pretty sure they are the same injectors. Yeah should be pretty easy. Enjoy!

 

Robby

[Guest]

Let us know how it goes! I am curious to see how it all works out for you!

 

and good luck!

[GPRACER]

I don't think you will need to change the PCM or even reprogram it. I just checked part numbers for 2 different w-bodies, the Grand Prix 3100 and the Impala 3400 use the same PCM, identical part number. I'm thinking one will work with the other. I have reflashed my PCM in my '95 with code from a 2001 worked fine.

[AM6_Cutlass]

Thanks for all the replys guys. I've decided to skip the engine swap for now. I took the car to another shop and the guy quoted me $1600 to do the swap. He asked me how many miles were on my 3100 and what was wrong with it. Said that it would be about $800 to do the head gasket, but it could still be the intake manifold gasket which would only be about $300. I'm dropping the car off there tomorrow. BTW: still for sale

[GnatGoSplat]

Damn, mechanical work sure is expensive if you pay to have it done! :yikes:

[NeverSayDie]

for real! a local dealer wanted like 500 bucks to change my dash pad...that was before I knew that there are only like 6 bolts holding it in. they also wanted to charge me for about 6 hours of labor. assholes!