LS newbie needing advice on engine swap

[AMGguy]

I have a 2003 SLK32 AMG and I want to do an LT1 (LS6?) swap in my car for various reasons. I'm a mod nut and got it to 450hp before I blew my engine and transmission and now it's an arm and a leg to replace. I can go through the long story if anyone is interested, but for the most part I'm tired of the Mercedes proprietary costly parts and I'm looking for something that's easier to find parts for and has a larger aftermarket. The tricky part is, I'm on a tight budget this summer.

Lets start with what I have already to work with:
I have a 1986 Firebird with a '96 LT1 swap and 4L60E trans and ECU and accessories that came out of a Caprice police interceptor, although I don't know much about the tuning. I want to use this car for the donor engine and transmission, possibly the ECU even if it's just for the 4L60E operation.
I have the LS6 block, heads, and internals from a 2003 Z06 corvette. (no accessories or manifolds)
Custom Megasquirt II ECU (formerly running my upgraded injectors on the Mercedes M112 engine)
Eaton AMG twin-screw supercharger (was running 23 psi on the benz after custom pulleys)
Holset HX35 70cfm VGT turbo (this was my next project and now it's just sitting here, any potential? was going to rear-mount it where I removed my factory resonator)

Some stuff will be used, some stuff won't, that's just the list of things I have to work with. I'm hoping I can get something that runs with minimal purchases. My uncle runs a machine shop which is how a lot of the mods I did on the Mercedes were possible (because there is very little aftermarket on it, and what's there is very costly). So I have that resource available if I need any custom brackets or machine work. I know I will need this to create the motor mount location brackets and possibly modify the crossmember for the transmission, and then of course a resized drive shaft.

I have a few questions since I'm pretty new to the LS6 and chevy engines regarding interchangeability on the LT and LS models. Most of the searches I found just gave basic differences between the engines, like "aluminum vs cast iron" and other specs that didn't really do much for me.

1) Can I bolt on my accessories and transmission right onto the LS6 block? I'm thinking of taking the LT1 setup and just upgrading the heads/block/internals with the LS6 stuff I have.
2) Can I use an aftermarket ECU (MSII) or even get a carburetor w/manifold and leave the existing ECU to just power the 4L60E transmission? This is the same setup I did on the Mercedes transmission since it was electronically controlled too. If I go this route, what sensors will I need to leave in place (or wire additionally) for the transmission to work right?
3) Assuming I go EFI and not carb, since I don't have the LS6 intake manifold, can I just use the LT1 intake? I don't mean compatibility with electronics (since I'm having to custom tune/harness anyways) but just a straight physical "will it fit properly?"
4) What aftermarket spark solutions do you recommend? I saw a few carb kits that came with timing/spark controllers. Should I bother with this or just run it all off the MSII?
5) Should I bother with forced induction on the car? I have a perfectly good supercharger I can mill the intake runners off of and custom make me a manifold and bracket for it. I would have to worry about hood clearance though. I also have this Holset turbo with 1k miles on it that I could rear-mount similar to STS style.
6) Will I need to change my radiator for the LT1 setup? LS6 setup? Current radiator flow enters the radiator at the top on the drivers side and exits on the bottom of the passengers side. I read about the "reverse cooling" on the LT1 but wasn't sure how that would effect the radiator compatibility and if it would even be an issue on the LS6 motor.

Right now I'm just trying to get the car running, even if it's not as fast as it can be initially (for example the inferior LT1 intake), then I can upgrade later when I have more money. I will likely hold off on the sc/turbo for now but I'm just throwing it out there to get ideas.

If anyone has input on any of these questions or if you have other concerns that I have not thought of yet, your input is very appreciated!

[c5z28]

lt-1 and ls-1 parts are not interchangeable, you can swap the tranny over but you will need a kit for that, i'm sure one of the sponsors can help w/ that or a more knowledegeable person than I. This sounds like an interesting project.

[Marc 85Z28]

I don't think you realize what you're in for.

Nothing interchanges between the LT1 and LS1. Even the transmission won't work without alot of time and money. Swapping in the LT1 would be a huge waste of time.

The wiring on this car is going to be the worst nightmare anyone could ever imagine. German cars, especially the later stuff, is impossible to figure out. Good luck getting anything to work on that car with all it's electronics.

Finally, if you're complaining about the price on Mercedes parts, realize that the rest of the car is just a likely to fail, and is just as expensive to repair.

This is not something that could ever be done on anything resembling a tight budget.

[JoshieDoom]

i agree it is going to be a nightmare. You need to choose which you want. If you want ls6 I would sell the lt1/4l60e and buy a ls6/ls1 with a 4l60e. It will save you a giant hassle.

I have no clue how the driveshaft and all that stuff would work. Good luck bro.

[AMGguy]

The wiring on this car is going to be the worst nightmare anyone could ever imagine. German cars, especially the later stuff, is impossible to figure out. Good luck getting anything to work on that car with all it's electronics.

Let me clarify on this project some.

First, the wiring doesn't bother me. I rebuilt the wiring harness on my car and wired in a custom ECU with all custom sensors and gauges and they say Mercedes are wiring nightmares and I have been told by people that have seen my work "if you can do this to a Mercedes, you can do anything". Wiring is my world when it comes to cars. The reason I need to clarify this project is because I think you have some sort of Mercedes integration in mind. I don't plan on integrating anything from my Mercedes at all, that's the point of the project. I plan on either using the LT1 ECU or using an aftermarket ECU and using all of the chevy sensors to go along with it. I even mentioned using a carb and doing away with 80% of the electronics anyways.

You answered my question on the interchangeability though, so the intake will not work. I found an intake for a carb setup for under $1k and I will likely go that route unless I find a good LS6 intake somewhere.

Regarding the transmission, I would like to know more about the integration of this. It's my understanding that the ECU only requires a small handful of sensors for the transmission to function. I'll have to do some research on which sensors unless someone on this board knows a bit more about it, but my plan is to just leave those sensors intact (or wire up new ones depending on the block) and then disconnect everything else from the ECU and let the aftermarket ECU or carb to do the rest. As far as I know, the bellhousings appear to be the same, I might need to just change the flywheel. If anyone has info on a kit for this let me know.

[JoshieDoom]

You answered my question on the interchangeability though, so the intake will not work. I found an intake for a carb setup for under $1k and I will likely go that route unless I find a good LS6 intake somewhere.

ls6 intake will not fit a lt1....

[AMGguy]

I have no clue how the driveshaft and all that stuff would work. Good luck bro.

I will have to get a driveshaft from the 4L60E and from my Mercedes into the differential, take some measurements after the transmission is mounted, take them both to a machine shop or custom driveshaft shop and tell them what size I need it and they'll make me one the right size using the ends off both parts and make sure it's properly balanced and things like that. Most places I talked to will do this under $200.

[JoshieDoom]

I will have to get a driveshaft from the 4L60E and from my Mercedes into the differential, take some measurements after the transmission is mounted, take them both to a machine shop or custom driveshaft shop and tell them what size I need it and they'll make me one the right size using the ends off both parts and make sure it's properly balanced and things like that. Most places I talked to will do this under $200.

Hmm sounds like you got a plan there.. crossmember will be fun as well

[AMGguy]

ls6 intake will not fit a lt1....

Right, and that is why I will need to get an LS6 intake for the LS6 motor.

[AMGguy]

Hmm sounds like you got a plan there.. crossmember will be fun as well

The crossmember I have not figured out yet. I was told it is much easier to do the crossmember work when I'm able to get the transmission under the car for more accurate measurements, so I will wait until after I pull my current trans unless I find a better way to do it.

[JoshieDoom]

I dont think you get what everyone is saying. You cannot upgrade a LTX block with a LSX components

An lt1 that came outta youre bird will in no way shape or form work with those

An lt1 car will have to be upgraded via LT4 parts

[AMGguy]

I dont think you get what everyone is saying. You cannot upgrade a LTX block with a LSX components

An lt1 that came outta youre bird will in no way shape or form work with those

An lt1 car will have to be upgraded via LT4 parts

Did you even read my top post? I said I was going to use one or the other. If I use an LT1 I already have everything I need but since I would benefit more from the LS6 block I'm trying to figure out what else I need.

For example, intake...

I found a belt/accessory kit for an LS6 for around $800. Seems to have everything I need.
http://www.crateenginedepot.com/stor...P1734C198.aspx

I also found an LS6 intake on that same site, but it was a bit more expensive than the carb setup, and I'll have to do more wiring.

So far I still disagree with claims that the 4L60E won't work with the LS6 block, I think it will. I saw an article where someone ordered an LS1 with 4L60E transmission. I'll see if I can dig it up. The bellhousings match up, anyone know about the flywheel?

Forums get so cluttered with input from people that do know and the people that pretend to know or are stuck "in the box" so to speak with only knowledge of factory configurations. I originally tried finding the service manuals to both of these motors to answer a few questions myself, anyone have any FSM resources on cars with these engines?

[AMGguy]

I dont think you get what everyone is saying. You cannot upgrade a LTX block with a LSX components

An lt1 that came outta youre bird will in no way shape or form work with those

An lt1 car will have to be upgraded via LT4 parts

Did you even read my top post? I said I was going to use one or the other. If I use an LT1 I already have everything I need but since I would benefit more from the LS6 block I'm trying to figure out what else I need.

For example, intake...

I found a belt/accessory kit for an LS6 for around $800. Seems to have everything I need.
http://www.crateenginedepot (dot com) /store/Accessory-Drive-with-air-LS1LS6-19155066-P1734C198.aspx

I also found an LS6 intake on that same site, but it was a bit more expensive than the carb setup, and I'll have to do more wiring.

So far I still disagree with claims that the 4L60E won't work with the LS6 block, I think it will. I saw an article where someone ordered an LS1 with 4L60E transmission. I'll see if I can dig it up. The bellhousings match up, anyone know about the flywheel?

Forums get so cluttered with input from people that do know and the people that pretend to know or are stuck "in the box" so to speak with only knowledge of factory configurations. I originally tried finding the service manuals to both of these motors to answer a few questions myself, anyone have any FSM resources on cars with these engines?

[AMGguy]

I dont think you get what everyone is saying. You cannot upgrade a LTX block with a LSX components

An lt1 that came outta youre bird will in no way shape or form work with those

An lt1 car will have to be upgraded via LT4 parts

This isn't what I'm saying at all... (sigh)

[AMGguy]

I dont think you get what everyone is saying. You cannot upgrade a LTX block with a LSX components

An lt1 that came outta youre bird will in no way shape or form work with those

An lt1 car will have to be upgraded via LT4 parts

Did you even read my top post? I said I was going to use one or the other. If I use an LT1 I already have everything I need but since I would benefit more from the LS6 block I'm trying to figure out what else I need.

For example, intake...

I found a belt/accessory kit for an LS6 for around $800. Seems to have everything I need. Can't post the link for some reason. moderator?

I also found an LS6 intake on that same site, but it was a bit more expensive than the carb setup, and I'll have to do more wiring.

So far I still disagree with claims that the 4L60E won't work with the LS6 block, I think it will. I saw an article where someone ordered an LS1 with 4L60E transmission. I'll see if I can dig it up. The bellhousings match up, anyone know about the flywheel?

Forums get so cluttered with input from people that do know and the people that pretend to know or are stuck "in the box" so to speak with only knowledge of factory configurations. I originally tried finding the service manuals to both of these motors to answer a few questions myself, anyone have any FSM resources on cars with these engines?

[JoshieDoom]

This isn't what I'm saying at all... (sigh)

Your post says you will be using it as a donor car. but it says you have a ls6 block from a vette. You will need everything off gen III engine for it to work.

[AMGguy]

Your post says you will be using it as a donor car. but it says you have a ls6 block from a vette. You will need everything off gen III engine for it to work.

I said I haven't decided yet, listed what I have, and asked what I would need to get each configuration work.

Anyways, I found a 99 SS with a hydro locked engine, drove through a flood and blew the heads right off the car (not literally off, you know what I mean). It's a 6 speed, trans works fine and has all the accessories and ECU. It's a friend of mine and it's been sitting in his garage for several years now rotting, I'm trying to talk him into selling it to me and I'll be able to get a lot of the other needed parts off that it sounds like. Maybe I can swap the block and heads with his.

On a different note, I've noticed a LOT of LS1's that come equipped with a 4L60E from the factory, why would anyone say it wouldn't work? I'm still searching for wiring schematics or a FSM if anyone has any links. Trying to figure out what sensors are required inputs for the ECU to make the trans work properly. I might just go dual ECU again (had to do the same thing on the Mercedes).

[AMGguy]

I found a site with some good info on the 4L60E, no wiring diagrams yet, but according to novak-adapt's 4l60e website the only sensors I will need is the VSS (Vehicle Speed Sensor... which I will need for my speedo anyways) and the throttle position sensor. Still doing research but I think I can wire sensors to those 2 inputs on the ECU currently connected to the trans and then set the ECU aside and use it solely for transmission control. Wiring nightmare? Not a chance, just 2 sensors from engine to ECU and then existing harness from ECU to trans!

[AMGguy]

I decided to use the LT1 (I know, I know! poor decision, right?) but since my budget is only around $2500 then I can get the LT1 swapped and running in the car much quicker and cheaper than the LS engine since I already have everything for the LT1 and will have a lot to buy for the LS1. I added up all the parts and upgrades for an LS swap that I would want and it would be a little over budget. Since I have another block to work with, I will probably build it up over the winter and possibly swap to the LS next year with a 6 speed. This way I'm not pressured into buying a lot of stuff I don't have in a short amount of time and I can just use something that I already know works.

Thanks for your input, answered a few of the questions regarding LT and LS that I wasn't sure about. I'll likely post my progress on this board if anyone is interested.

[ls1fan74]

wow, subscribing to this-I know some ppl swap LS1's into their 3.8 camaro/bird but the advice to them is mostly "for the amount of $$ just buy a Z28" I wanna see how difficult this turns out to be. good luck tho