Ok, I have tried looking around on the site for this answer, but I could not find it.
I was wanting to know if the 2007 5.3l V8 will fit into a 2000 ls. I understand there will need to be a transmission change to handle any engine other that the puny 3400 in it now...

 

if you look at a 00-05 and a 06-07 camparing the two it look damn near identicle just update to the body and interior and dif engine options i don't see why it wouldn't work

 

i think it could... just as long as the front wheels are the same width apart as the 06-7, only other spot i could see difaculties would be the firewall. it could possibly be wider in the o6-7 cars to allow more clearance for the V8. and the fact you would probibly have to swap the wireing harness along with alot of the computer crap. oh, and the front suspention might be a lil beefer on one of the v8 cars than the v6 cars to handle the extra weight of the v8. if you were gonna do this swap, a wrecked donor car would probibly save you alot of time & agravation

 

I looked into this option and there was a discussion on it, the result for me was an turbo for a little less price and more hp boost.....if thats what your looking for

 

I would deff go Turbo. With all the money you're looking to invest into that swap you could get a Z7 from ZZ Performance, an HP tuner and money left to beef up the suspension.

 

Remember he has the 3.4 right now...

So he would have to drop in a 3.8 then turbo it.

Honestly, it would probably be cheaper for you to sell your car and get one with a better engine if you wanted to swap then turbo. Or just sell your car and find a supercharged version and play with the L67.

Or just do the 3.8 swap. But we are talking $$$$ to go from the 3.4 to a newer engine + spending money on boosting that engine.

 

You could not find the answer because no one has done it that actively posts on here.

It is possible, and shouldn't be terribly hard- I'd just get a complete powertrain including wiring from a donor car and swap it all.

Someone correct me if I'm wrong, but doesn't a 00 3400 have a 4t65? That would make it for the most part the same as what comes with the 5.3.

 

You are correct.

All of the 2000+ Monte's came with a 4t65e transmission.
The only difference in them is gearing, aside from the hardened diff/diff cover/pass side axle that came on the 4t65e-HD.
Seems to be a lot of confusion about the transmissions in these cars, and the differences between them.

The only thing that I'm not positive about is the bellhousing pattern between the different engines. I'm pretty sure that when I was researching a 3.4L to L67 swap, I found that the bellhousings for the transmssion that came with each engine is identical. Not sure about the 5.3L V8 transmission though.
I doubt that there is any difference anyways, as GM likes to keep things simple.

Around 2003 GM did make some overall changes to every single 4t65e transmission which has caused some problems for people that want to put a later year transmission in an earlier year car. Clubgp has a few threads about this, and tripleedgeperformance.com has some details on what was changed and why the newer transmissions aren't plug and play in the older cars.
-Riggs.

 

I would definitely reccomend him swapping transmissions anyways- it'd be easier since you know the whole powertrain already works with that wiring and that pcm. Also, I think there have been a few minor internal upgrades over the years that would be nice also.

I was just saying that to let him know that his transmission really isn't all that different from what he'd be swapping to.

 

Since you would have to swap in the PCM for the 5.3L V8, you already have all the tranny info on it. There should be no problem at all with the tranny. Theres would only be a problem if you were using an older PCM with the newer tranny.

As long as its a full swap, engine tranny, wiring harness, and pcm you should have no problems except fitment.