LT1 swap

[454Chevy]

dose anyone knows what needs to be done to swap in a LT1 on a v6 1983 C-10 truck

[Blue Bowtie]

You're going to have to REALLY want to perform the swap in order to see it through. The engine and transmission should bolt in just like it was made for it so long as you use the V-8 mounts for the truck. You may have to alter the position of the transmission mount or crossmember, depending upon which transmission is currently installed. Adding an expansion tank for the cooling system, and mounting the twin electric fans should complete the bulk of the hardware changes.

Fortunately, the 1983 should already have an ECM installed, so some of the necessary wiring will already be present, and the mounting for the ECM can be used for its replacement.

Beyond the mechanical changes and plumbing, you'll need to install an electric fuel pump in the tank (or near it), install all new fuel lines including a fuel return line, install a wire harness for an LT1, and install either a PCM or ECM to control it all. It is far easier to use a 1993 Y-Body ECM and reprogram accordingly. The later PMs are a little less forgiving.

As part of installing the wire harness, you'll need to install an extra brake pedal switch, provide extra fuses for the injector power, ECM power, transmission power (if you're using an automatic), and install an electic speedometer to accept the VSS signal.

Having a complete engine, transmission, cooling system, fans, and a complete wire harness with all the sensors and relays from a donor vehicle is easiest. Trying to piece it all together is a nightmare, and gets costly. I've done EFI conversions, and have it down to about 45 man hours if everything goes well. That is exclusive of the seemingly never-ending PROM tuning and data collection.

[454Chevy]

Originally Posted by Blue Bowtie

You're going to have to REALLY want to perform the swap in order to see it through. The engine and transmission should bolt in just like it was made for it so long as you use the V-8 mounts for the truck. You may have to alter the position of the transmission mount or crossmember, depending upon which transmission is currently installed. Adding an expansion tank for the cooling system, and mounting the twin electric fans should complete the bulk of the hardware changes.

Fortunately, the 1983 should already have an ECM installed, so some of the necessary wiring will already be present, and the mounting for the ECM can be used for its replacement.

Beyond the mechanical changes and plumbing, you'll need to install an electric fuel pump in the tank (or near it), install all new fuel lines including a fuel return line, install a wire harness for an LT1, and install either a PCM or ECM to control it all. It is far easier to use a 1993 Y-Body ECM and reprogram accordingly. The later PMs are a little less forgiving.

As part of installing the wire harness, you'll need to install an extra brake pedal switch, provide extra fuses for the injector power, ECM power, transmission power (if you're using an automatic), and install an electic speedometer to accept the VSS signal.

Having a complete engine, transmission, cooling system, fans, and a complete wire harness with all the sensors and relays from a donor vehicle is easiest. Trying to piece it all together is a nightmare, and gets costly. I've done EFI conversions, and have it down to about 45 man hours if everything goes well. That is exclusive of the seemingly never-ending PROM tuning and data collection.

I have a donor car its a 1994 caprice I will use the wire harness and the ecm and I am using the 4l60 I dont know if i can use a 700r4. do you know if they sell any books for this swaps

[Elbert]

I would use the transmission that's connected to the LT1. You need to get a larger radiator for sure. Better take some good pictures and notes if you are not familar with the engine in the car. I would suggest you buy a shop manual that matches the 94 caprice so you will have some reference points.

Don't the LT1 engines run electric fans and have no provision for a fan clutch? If that's true then you might could swap the electric fans off the car on to your truck after you get a 3 or 4 core radiator designed for a V-8 C-10.

I'm guessing the motor mounts are configured differently on your truck for the V-6 as they would be for a V-8. Find a buddy with the same or similar year model pickup with a V-8 and get the motor mounts and install them like the reference truck. You will also have to figure out how to get an electric fuel pump setup correctly with the correct pressure to feed the LT1.

Get all the crap off the doner car, and I mean everything under the hood. Get a digital camera and take a bunch of pictures. Most of the wiring harness have plugs that can only work one way. Get some tape and mark the wires so you know where they go.

Don't skimp on the right radiator.... the one out of the car might work?

[454Chevy]

painless wire sell an after market wiring kit for the lt1 conversions do you think I should go with painless or some other on they sell on ebay for 100 $ But I have to make all the splicing or they could do it for me for 250 $. Thank you guys for youre help

[CD Smalley]

Painless all the way. You might look at Street and Performance as well. I think their website is http://www.hotrodlane.cc/

They are probably your two best sources of harnesses and info.

[Elbert]

I would certainly use painless if your budget allows. getting the old harness out of the car would take some time.

[1968 Pontiac]

Find a 94-96 police cruiser or taxi, the HD cooling option on them should be clutch fan, not electric fans as came standard on civvies and most cruiser/taxis.

For your rad, use one from a diesel truck.

Use an aftermarket electric fuel pump which remote (underhood) mounted pressure regulator with in line fuel pressure gauge.

If you truck was a 4.3 you can use the LT1 mounts, or you can use a set of truck mounts but I think they sit higher then car mounts.

If you find a cruiser/taxi, they usually came with separate oil, tranny, and power steering cooler. Another reason to use the car mounts, because the oil cooler lines are supported on the mount a little differently than they are on a truck. Also the line connections at the block are different between car & truck.

[CD Smalley]

The 9C1s came with dual electric fans. I don't believe there was any other option. The civvie cars with the heavy duty cooling option came with the mechanical fan.

[Elbert]

I thought all LT1 engines were cooled by electric fans? Don't they have a totally different water pump than a regular 5.7 350?

[CD Smalley]

The LT1s with electric fans had the water pump driven by a camshaft.

Some of the civvie cars were given a mechanical fan, with an additional electric. Not sure how that effected the water pump. My guess would it would have to have been belt driven then.

[silicon212]

Originally Posted by CD Smalley

The LT1s with electric fans had the water pump driven by a camshaft.

Some of the civvie cars were given a mechanical fan, with an additional electric. Not sure how that effected the water pump. My guess would it would have to have been belt driven then.

The mechanical fan on the heavy-duty cooling option on the Caprice was belt-driven, but the pump is still cam-driven. The mechanical fan is offset on what looks like an idler pulley.

The 9C1s could also have a belt driven cooling fan, again as a part of the heavy duty cooling system.

[CD Smalley]

I have never seen an LT1 powered 9C1 with a belt fan. Never even heard one talked about before in over 10 years on the 9C1 email list.

[2000CAYukon]

Originally Posted by CD Smalley

I have never seen an LT1 powered 9C1 with a belt fan. Never even heard one talked about before in over 10 years on the 9C1 email list.

9C1s and non-Impala SSs did have an option for a mechanical fan. Still a LT1, still a can driven water pump, just one electric fan and one mechanical fan. This option was called RPO V08 Heavy-Duty Cooling System. Impala SS did not have this option (I think) and came with dual electric fans. For 9C1, it depends on how is was ordered.

See http://www.theherd.com/articles/fan-replacement.html

//2000CAYukon

[CD Smalley]

Interesting... I have seen civvie cars with that option. Still have yet to see a 9C1 like that. They must be fairly rare.