Early C4 LS swap video
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,876
Likes: 764
From: Sligo PA
Early C4 LS swap video
So I had some time to kill today. I have been wanting to make a video for a while about some of the things I learned about LS swapping these cars. So this video is my opinion and things I've learned. YMMV. This isn't a video about how to LS swap a C4. More about tips and tricks. Also some things I would have done differently if I had to do it over again. And some things I learned that made the swap financially possible on a budget. Sorry it's so long. I hope this helps someone who is debating how to approach an LS swap.
Burning Brakes
Joined: Nov 2015
Posts: 762
Likes: 94
From: Airdrie Alberta
Hey Phobos, curious on what ls efi controller did you go with? I switch mine from fast efi to the FI tech as I'm planning on running boost. My kid built a L33 5.3/flat top with a set of home ported 799 heads, mild cam sloppy stage 2. The engine runs pretty decent, just have to find time to get the project finished.
Thanks for sharing your build.
Thanks for sharing your build.
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,876
Likes: 764
From: Sligo PA
Hey Phobos, curious on what ls efi controller did you go with? I switch mine from fast efi to the FI tech as I'm planning on running boost. My kid built a L33 5.3/flat top with a set of home ported 799 heads, mild cam sloppy stage 2. The engine runs pretty decent, just have to find time to get the project finished.
Thanks for sharing your build.
Thanks for sharing your build.
Burning Brakes
Joined: Nov 2015
Posts: 762
Likes: 94
From: Airdrie Alberta
Thanks for the update. I want to use the holley ecu for my next hemi project that I want to put into my pick-up. Both of my ecu worked good, but I wanted to run boost and FI was the cheapest route, plus it was on the shelf at my local hot rod shop.
Instructor
Joined: Aug 2016
Posts: 209
Likes: 24
Nice video. Answered several of my questions and helps me visualize several things. I'm wanting to do a swap in my 94 which sounds like I could get away going super cheap and stage it. I already have the electronic 4L60 which isn't the best but I could swap in and run it til it blows then put in a 4L80. And do the same for the Dana 36 in my car. I wish I could get any LS for $200 here in Colorado. Even the U Pull and Pay franchise here in Colorado is more then that (just base engine and heads is $290 + tax and they hit you for every little thing you leave on the engine like intake and injectors will add $40 and the 8 injectors will be another $56) and I think the employees pull all of the decent LS engines and sell them on Ebay before they ever hit the lot. Most of the stuff that still has an LS in it are super clapped out and you have to dig under 4 inches of grease to even see if it's an LS then you find out that it has 300K on it already. So much for a cheap swap with one of those engines. Maybe I need to take a road trip to PA 
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,876
Likes: 764
From: Sligo PA
Nice video. Answered several of my questions and helps me visualize several things. I'm wanting to do a swap in my 94 which sounds like I could get away going super cheap and stage it. I already have the electronic 4L60 which isn't the best but I could swap in and run it til it blows then put in a 4L80. And do the same for the Dana 36 in my car. I wish I could get any LS for $200 here in Colorado. Even the U Pull and Pay franchise here in Colorado is more then that (just base engine and heads is $290 + tax and they hit you for every little thing you leave on the engine like intake and injectors will add $40 and the 8 injectors will be another $56) and I think the employees pull all of the decent LS engines and sell them on Ebay before they ever hit the lot. Most of the stuff that still has an LS in it are super clapped out and you have to dig under 4 inches of grease to even see if it's an LS then you find out that it has 300K on it already. So much for a cheap swap with one of those engines. Maybe I need to take a road trip to PA
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,876
Likes: 764
From: Sligo PA
Nice video. Answered several of my questions and helps me visualize several things. I'm wanting to do a swap in my 94 which sounds like I could get away going super cheap and stage it. I already have the electronic 4L60 which isn't the best but I could swap in and run it til it blows then put in a 4L80. And do the same for the Dana 36 in my car. I wish I could get any LS for $200 here in Colorado. Even the U Pull and Pay franchise here in Colorado is more then that (just base engine and heads is $290 + tax and they hit you for every little thing you leave on the engine like intake and injectors will add $40 and the 8 injectors will be another $56) and I think the employees pull all of the decent LS engines and sell them on Ebay before they ever hit the lot. Most of the stuff that still has an LS in it are super clapped out and you have to dig under 4 inches of grease to even see if it's an LS then you find out that it has 300K on it already. So much for a cheap swap with one of those engines. Maybe I need to take a road trip to PA
This Saturday the one in Pittsburgh is having a sale that's whatever you can pick up and carry 20 feet for $50. I don't really need anything. But I'm going just to watch people get crushed.
Melting Slicks
Joined: Mar 2001
Posts: 2,150
Likes: 304
From: Timra, Sweden
I don't agree on the digital cluster. I don't see any reason to remove it unless you want to. It uses its own sensors. You need a tach signal and a speedo signal. The aftermarket ECU should be able to provide both. The only functionalities you loose are MPG data and fuel range that is calculated from MPG data.
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Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,876
Likes: 764
From: Sligo PA
I don't agree on the digital cluster. I don't see any reason to remove it unless you want to. It uses its own sensors. You need a tach signal and a speedo signal. The aftermarket ECU should be able to provide both. The only functionalities you loose are MPG data and fuel range that is calculated from MPG data.
I'm not saying that using the factory cluster is impossible. It just makes things harder.
Melting Slicks
Joined: Mar 2001
Posts: 2,150
Likes: 304
From: Timra, Sweden
The speedo signal is a little tricky. The output from the Holley ECU's (other than the Dominator) is a square wave PWM-. Being that it pulses the ground instead of a positive signal the factory speedo won't work. That's according to Holley anyway. You might be able to adapt the signal with a transistor circuit as a boost. Or you could use a GPS sender to the factory speedo.
I'm not saying that using the factory cluster is impossible. It just makes things harder.
I'm not saying that using the factory cluster is impossible. It just makes things harder.
Last edited by JoBy; Oct 26, 2021 at 03:18 AM.
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,876
Likes: 764
From: Sligo PA
In case anyone is interested and you live anywhere near Pittsburgh, PA. The salvage yard I mention in the video is having a sale this Saturday (10/30). On their Facebook page it simply said "Anything you can carry for $50". But then they released a video with the rules for the sale. They are adding to it "anything you can drag 20 feet for $200". This includes truck bed liners and anything in them. So as long as your not a morbidly obese smoker you could get an LS motor of your choice with a transmission and all the accessories and harness/PCM for $200+tax. The only issue is there is no warranty when you get a motor on a sale like this. Check out their video. I'll be there at 8:30 am on Saturday. I would be willing to help a forum member pull a motor if you help me.
Instructor
Joined: Aug 2016
Posts: 209
Likes: 24
Wish I could be there. Hey next time you are bored I would love to see a run and drive video. Talk a little about how it handles with double the HP then the 84 had stock. You moved quite a bit of weight around with the new drive train are there any suspension upgrades you feel are needed now after the changes? I autoX mine pretty hard so keeping my handling as good as it can be is an important consideration before I make any major changes.
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,876
Likes: 764
From: Sligo PA
Wish I could be there. Hey next time you are bored I would love to see a run and drive video. Talk a little about how it handles with double the HP then the 84 had stock. You moved quite a bit of weight around with the new drive train are there any suspension upgrades you feel are needed now after the changes? I autoX mine pretty hard so keeping my handling as good as it can be is an important consideration before I make any major changes.
The car is a Z51 car. I have new Bilstein shocks and a thicker sway bar in the back. I lowered the rear a little with longer bolts. Then I used QA1 coil overs in the front with 550 lbs springs. I have the QA1 shocks set to the middle position. I also have poly bushing all the way around. The handling is close to stock. I need to play with the settings on the QA1's. I just never messed with it. But being I'm just doing burnouts and smoking unsuspecting Mustangs light to light, fine tuning the suspension just hasn't been a priority yet.
Drifting
Joined: Mar 2018
Posts: 1,362
Likes: 400
From: DFW TX
My 500hp 6.0L 2900lb '84 is flat out scary. I learned real quick not to mess around under full throttle unless I was familiar with the road. My 84's suspension is so stiff that the car will jump off the road when it hits dips, bumps, ruts, whoopity doos...etc, especially when under throttle or around turns. It would probably be excellent at a twisty track but for my 84 on the public roads you have to be really careful when you use the happy pedal.
Another danger to look out for is the sleeper effect. No one expects an old krusty 84 Corvette to have 500hp. Gotta keep an eye out for the no look lane change from the driver of the slower car that thinks he is faster.
Another danger to look out for is the sleeper effect. No one expects an old krusty 84 Corvette to have 500hp. Gotta keep an eye out for the no look lane change from the driver of the slower car that thinks he is faster.