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Discussion Starter · #1 ·
Hi Folks,

As time rolls on, more and more people will likely be interested in swapping out their older motors for a more modern LS engine. The benefits to fuel economy and choice, horsepower, and torque--not to mention the easy of a Fuel Injected start--are innumerable. There are a ton of resources around the Internet on this very topic, and that is the problem--it's overwhelming!

So, I figured I'd start this thread on resources for swapping to an LS motor. Keep in mind, I have not done this myself but I plan to--and here I will simply share the information I have collected. This is FAR from everything and some of it will be plain wrong--so please lets chat about this and build a resource for other Impala owners looking to do this swap.


Starting from the rear to the front end:

1) Fuel - I didn't know this but your stock fuel system won't handle an LS swap. LS motors require 58 PSI in the fuel line, which may necessitate an upgraded line. The stock tank needs a bit of tinkering too--in order to ensure the fuel PSI is maintained, you will need a tank with baffles in it to prevent the fuel from sloshing away from the in-tank pump during acceleration, cornering, and stopping. I have read that in-line pumps are not ideal for LS motors.

2) Drive Shaft - You may need to get it shortened.

3) Transmission - You can get a kit that will bolt up any old small block chevy transmission to an LS motor. Or, you can use the stock transmissions. This is an area where I'm a bit weak.

3) Electronics - You'll need to either re-wire the factory harness from the LS donor, or you'll need to purchase a specially designed wiring loom from a place like Painless Autowire. In addition, there are all kinds of emissions issues and anti-theft devices built into the computer on the LS motor, which you will need to have reprogrammed. There are plenty of places and ways to do this programming but it will have to happen.

4) The Engine - We are working with big cars, but even still, space may be an issue. The oil pan can sometimes hit the crossmember, and you'll need to replace it with a different one. GM does make pans that will fit, and there are plenty of aftermarket options. Additionally, the engine mounts on LS motors are different then SBC (small block chevys) and BBC (5 points if you can figure that out :p) and so a specific conversion kit is necessary to bolt it in. Finally, there are accessories on the front end that all connect to a serpentine belt that will change if the engine will fit in your application.

In addition, there are quite a few variations on the LS motor for you to choose from. Seems that the best place is an automobile wreckers, but selecting your specific engine is probably best done with the help of Wikipedia:

http://en.wikipedia.org/wiki/GM_LS_engine

http://en.wikipedia.org/wiki/GM_Vortec_engine#LMG

And a handy guide for what these engines put out:

http://www.ls1tech.com/forums/conversions-hybrids/1369110-lsx-engine-identification.html

There are a LOT more details then what I've covered, but let's pool our knowledge a bit to provide some guidance.

Where can one get conversion kits? Baffled fuel tanks? Has anyone done a swap and if so what kinds of mods did you have to make to your car?

Cheers
Craig
 

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Starting with your bullets:

1) The in-line fuel pump needs to be submersed in the tank to cool the gas pump motor. You need 74 psi to the fuel pressure regulator on the fuel rails. The fuel pressure regulator returns the unused fuel (not the pressure differential) to the tank which enters the tank as far away from the pick-up as it can be mounted to reduce turbulence. A modern gas tank is indeed baffled and it is also deeper than an older car's gas tank was so that the pump stays submerged in gas even when you are sucking fumes. All lines have to be stainless steel and the tank has to be stainless or plastic to resist corrosion with E-15 gas today.


2) Drive Shaft - You may need to get it shortened. Short answer: maybe maybe not. It depends upon your choice of rear end and transmission. A 1958-'64 rear end will not hold up to the three hundred and thirty to five hundred horsepower your average LS-x outputs. You will need at a minimum a Corporate ten bolt, but a 12 bolt Spicer would be better and a Dana 60 is our best choice.

3) Transmission - The LS-x block uses the same bolt pattern as every Chevy engine made before it this side of the stove bolt six. Where it differs is the depth from the mounting surface to the crankshaft flange, but they make adapters for any tranny you want to install. The computer that controls the engine is looking for inputs from an electronic computer controlled transmission (4L60e, 4L65e, 4L80e or the the new six speed Allison).

3) Electronics - Chevrolet offers a brand new wiring harness that will install any LS-x motor into any Chevy car or light truck (it is made to be universal and just plugs in).


4) The Engine - There are four LS-x engine applications. The F, Y, and W body as well as the light truck.

The F-body is the fourth and fifth generation Camaro that is the most popular choice for front accessory drives and the intake manifold. Keeping in mind that the LS-x is modular and you can even take off an intake manifold and reverse the air inlet location if you want so mixing and matching components is not only easy but encouraged to make things fit.

Y-body. The venerable Corvette. Every body wants a 'vette motor because they are better than any one else's motor right? Wrong. The Corvette has a different intake manifold to clear the low hood; a different cam to improve the exhaust sound, different exhaust manifolds and pipes (to magnify that cam sound) but that is the only mechanical difference in the motors (they do have those big red plastic top covers that say Corvette but that doesn't make it go faster). The reason you don't want a Corvette motor is two fold the oil pan and the front accessory drive are designed to fit a Corvette body and won't fit well in your car (the front accessories are all mounted low to clear the low sloping hood, and the oil pan is deep because the motor is mounted behind the front cross member).

The W body Cadillac motors are the best choice for oil pans as they most closely resemble what you will find on your old small block Chevy. (the Camaro F-body is a good second choice but it will require modifications). They also are a good choice for an intake.

Finally light trucks. The only thing off a light truck that will fit easily in your car is the motor itself, but they offer the best short blocks. All LS-x car engines use an aluminum block and are sized at 5.7, 5.3 or 4.8 liter engines. A pick-up truck used the same size car engines but adds a bigger 6.0 liter motor that also has a cast iron block instead of the aluminum block used in all cars. A truck has a taller intake manifold that won't fit under many car hoods, and the accessories are mounted high on the block, which also get in the way.

So your best LS-x will be out of a bunch of vehicles as you grab the best of what you want you need to build your motor out of the parts available. A truck short block, heads and front drive accessories off a Camaro and the intake and oil pan off the Cadillac, with of course Corvette engine covers and possibly a corvette cam and torque converter in your computer controlled transmission.

Big Dave
 

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Discussion Starter · #3 ·
Great information, Dave!

I'm personally leaning towards the 5.3 l out of a 2006-current Chevy Avalanche or Silverado. I hear what you are saying about the truck motor and fit, and I fully anticipate having to do some modifications with regards to the components. But, 300 + HP and torque, in addition to being able to run on Ethanol, means my dear car will look great AND run great :)

Really great information in that post! You sir are the backbone of this forum with your knowledge!

Regards
Craig
 

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I am doing a swap into my 58 Impala convertible. I am using a 2001 5.3 truck engine and a 700R4. I mounted it with mounts using the front top bolt of the 58 mount int he front top hole of the 5.3. This set the motor so the that the drive shaft that I used with the TH350 fits the 700R4 and the transmission mount is only a matter of a 4"x6"x1/4 plate of steel with 4 holes in it. the motor orientation is such that I will be able to use the 58 348 fan shroud and the 5.3 mechanical fan. For the exhaust I will be able to use the F-body exhaust manifolds with some slight modifications.

As for the fuel system I am going with the in-line external fuel pump (Walbro) a lot of guys out there are using them and they are well proven. I will have to tackle that baffle in the gas tank issue later if I find I have a problem.

As for the rear diffs holding up all I can say is that they held up under 409's with 4 speeds. My brothers and I went through a ton of these 58 to 64 full size cars back in the late 70's and early 80's, with all manner of different HP rating and never blew one up under hard street use. (When I left for college in 1980 we had 240 cars in our yard and 95% were 1970 and older Chevy's) Parts are still available and tech builds to keep them alive under extreme use are still out there. Don't get me wrong though, if you have the $$$ to spare Go with a more contemporary differential. I am sticking with my 3:70 Posi. I am not going to do burnout contests or try for the season record holder at the 1/4 mile. I just plan to put lots of miles on it because I love to drive it. By the way the weak point on these stock units are the main caps. There are steel upgrades out there and for extreme situations steel main caps and bolt mods will keep them alive.


The oil pan was the hard part so far, I Chose to modify the truck pan. With the engine mounted where I have it no stock pan would work. The kits that are out there sit the engine farther back up about an inch higher so the CTS or the F-body pans work with them. The way I chose to do it let me keep more of my original components in place like the fan shroud and the drive shaft.

I will try to keep you all posted but this post I am doing at after midnight on a Sunday and I should have been in bed long ago.

also I haven't figure out how to post pictures yet but I will so you can see some of the work in progress.
 

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Discussion Starter · #5 ·
I would definitely love to see some pictures, if you need a had figuring it out shoot me a PM.

Good to know those walbro pumps do the trick--it is more reasonable to keep the tank intact rather then risk a leak/bad weld by modifying it unless I have a problem later on.

Cheers
Craig
 

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Here's a couple pic from my LS install in my 62 Impala Vert.


Damn Chucc, you just had to show off didn't you!:D
 

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...

As for the rear diffs holding up all I can say is that they held up under 409's with 4 speeds.
I cut my teeth on small block Chevys and the 409 back in the early sixties. I couldn't afford a new car so I hot roded a 1953 Chevy 150 two door sedan. I had a 425 horse 409 in it that I built using a truck block and service parts. I can testify that the rear end found in 1958-'64 Chevy's will not hold up to the power of a 409 (it is the reason Chevy bought a rear end from the Dana corporation's Spicer division to put into all cars made from 1965-'72, because of warranty claims on the old rear end costing them too much money).

I got to be very good at rebuilding rear ends as I could break one on demand, because the spider gears are too weak to hold the torque of either a hot small block or a Mark I big block (348-409 W motors). If the end gear didn't break, it was the idler gear. Occasionally I could break an axel (which is the same 28 spline axle size used in the ten bolt Spicer rear end that every one wants to upgrade to a twelve bolt Spicer because they are notoriously weak and are know to break axles first).

Big Dave
 

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you can use a hummer oil pan on a 65 -70 but custom headers have to be built and the c member notched, but it totally worth it. my 68 impala runs just as well as my 2001 silverado. hmmm wonder why?
there was also an aluminum block 6.0 used in trucks but not many of them out there
 

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I'm restoring a 62 Impala that I want to put a LS engine into. What I need is info on the swap and where to buy a fuel tank for this app? I'm a long ways from putting this all together but, looking for all info. Thanks
 

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Welcome to the Team Rocketman!

Best bet is to buy an aftermarket all stainless custom gas tank that is designed to fit your car but has holes sized to accept a Chevy in-tank fuel pump return lines as well as the vents and fuel level sender.

Rock Valley sells them as well as these guys:

http://www.tanksinc.com/index.cfm/p...tegory_id=124/home_id=-1/mode=prod/prd409.htm

The more power you plan to you make the more pounds of fuel per hour injector you will need as well as a larger fuel pump to cover the increased demand (not using the stock Chevy pump but an aftermarket pump such as Aeromotives EFI A1000 pump). Before you abandon GM though consider that GM made a motor as large as 7.0 liters as of now rated at 560 horse. If you use all stock parts your computer will work with what you have (you still may have to reflash in a new program, but you know the communication signals will be acceptable).

Big Dave
 

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A lot of good info here. Thanks for all the posts. I started a thread earlier before i noticed this one Sorry. I'm doing a LS swap in my 67'. Not doing it myself because i'm out of pocket at the moment.
 

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I did a LS swap in my 68 C10 and after doing it and driving it I will never go back. I now got a 61 Bel Air I am wanting to do a swap in as well.
I'm along for the ride...

Trevor
 

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you can use a hummer oil pan on a 65 -70 but custom headers have to be built and the c member notched, but it totally worth it. my 68 impala runs just as well as my 2001 silverado. hmmm wonder why?
there was also an aluminum block 6.0 used in trucks but not many of them out there
Doesn't the hummer pan hang down to low? I've heard that the holley pan is the way to go.
Ideally, you wouldn't want the pan hanging below the crossmember.

-Nick
 

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Yes he sort of mentioned it as being the best fit he had found using GM cast aluminum pans. But he did mention it won't fit without a lot of fabrication because you have to notch the front cross-member to clear the pan then brace it to get the strength back.

There really is only two ways of getting a pan that fits. Buying and aftermarket pan or cut, slicing and welding your own custom cast aluminum pan out of several used GM pans which to me is expensive and subject to leaks as I am not that talented with a TIG torch.

Big Dave
 

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I bought the GMPP muscle car oil pan and put it side by side with the truck pan and it was pretty much the same.. . Looking for a F-body pan.. I read on ls1tech that the F-body pan is the best fit without modifying the front cross member.
 

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We are in the process of putting a 2002 5.3 in our 60. The GM performance oil pan hangs too low. We have a friend who used one on his 62 wagon and it hung down way too low. LS1 tech is a great research tool. Everyone says the 98-02 Camaro (f-body) pan is the way to go. We bought a used one, but they are expensive. We also notched the crossmember. We have learned alot in the last couple months and we still have a ways to go.

Here is a photo of our cross member notch.

 
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