Replacing 84 engine
Thread Starter
Burning Brakes
Joined: Apr 2004
Posts: 1,032
Likes: 197
From: Atoka, TN
Replacing 84 engine
I’m planning to replace the crossfire/L-83 on my C4 and have been searching for some answers on the 3 options I’ve narrowed down to.
1st choice is the Ramjet 350. Will it clear the stock hood?
2nd choice is the GMPP EFI ZZ6. With it having multi port EFI, but a downdraft type throttle body, has anyone stuffed it into a C4? What air cleaner set up did you use.
3rd choice is an LSX. Last choice because it requires engine and trans. Is there a list of exactly what I need to find? I want to keep my a/c and don’t want to invest a ton of hours trying to figure out what works. The threads I’ve read are a bit vague when it comes to descriptions and part numbers.
My goal is reliable performance. 300’ish hp at the tires. I am planning a cross country trip next year so reliability can’t be overstated.
Any help will be appreciated.
Chris
1st choice is the Ramjet 350. Will it clear the stock hood?
2nd choice is the GMPP EFI ZZ6. With it having multi port EFI, but a downdraft type throttle body, has anyone stuffed it into a C4? What air cleaner set up did you use.
3rd choice is an LSX. Last choice because it requires engine and trans. Is there a list of exactly what I need to find? I want to keep my a/c and don’t want to invest a ton of hours trying to figure out what works. The threads I’ve read are a bit vague when it comes to descriptions and part numbers.
My goal is reliable performance. 300’ish hp at the tires. I am planning a cross country trip next year so reliability can’t be overstated.
Any help will be appreciated.
Chris
Last edited by cmashark; Jul 14, 2021 at 05:14 PM.
Melting Slicks
Joined: Mar 2002
Posts: 2,874
Likes: 764
From: Sligo PA
I think it comes down to budget and time. An LS would easily meet your power goals and be the most reliable option, also probably the lowest cost. But it will require the most amount of time. I love mine and I could't imagine the car without 400 hp to the wheels. I can't speak to AC because I don't have a use for it and removed it from the car before the LS swap. But as far as the motor and trans go if your car is an automatic then all you really need is a good salvage yard 5.3L or 6.0L with a 2wd 4L60e with a harness. You will need to download software. I like PCM Hammer. Also LS Droid works well. They are both free. Use them to remove VATS and emissions. Then you can easily modify the LS harness to be stand alone. The only real issue is fabricating the C beam adapter. Just do a search here. There are tons of threads about it. If you have any welding ability it's not hard at all.
Racer
Joined: Feb 2020
Posts: 483
Likes: 109
From: Fairfax, Virginia
What trans do you have/want?
The LS swap is the most reliable by far, modern tech, easier diagnostics, and no need for a specialized tuner or shop 300HP is easy thats just a cam swap, which is simple and quick to do with the motor out.
I'm currently working on getting AC in my LS swap project C4, I was going to swap to a Sanden compressor but bailed and instead went for a system recondition with a parralel flow condenser and beefier fans to pull more heat out of the insufficient fin area of any 134a condenser that will fit in a C4. The 85 apparently uses the 5 inch clutch on the R4 so you need a Cadillac R4 LS swap bracket, $110 from Ebay for a CNCed bracket with 2 rear supports, it should just barely clear the upper control arm. I also went for a shrouded aluminum radiator with 2 11" fans, my C4 had a leak in the pass side tank that caused it to drain the coolant whenever it ran. Should be frosty and the larger fans will help the LS stay cooler in the heat.
The LS swap is the most reliable by far, modern tech, easier diagnostics, and no need for a specialized tuner or shop 300HP is easy thats just a cam swap, which is simple and quick to do with the motor out.
I'm currently working on getting AC in my LS swap project C4, I was going to swap to a Sanden compressor but bailed and instead went for a system recondition with a parralel flow condenser and beefier fans to pull more heat out of the insufficient fin area of any 134a condenser that will fit in a C4. The 85 apparently uses the 5 inch clutch on the R4 so you need a Cadillac R4 LS swap bracket, $110 from Ebay for a CNCed bracket with 2 rear supports, it should just barely clear the upper control arm. I also went for a shrouded aluminum radiator with 2 11" fans, my C4 had a leak in the pass side tank that caused it to drain the coolant whenever it ran. Should be frosty and the larger fans will help the LS stay cooler in the heat.
Thread Starter
Burning Brakes
Joined: Apr 2004
Posts: 1,032
Likes: 197
From: Atoka, TN
Thread Starter
Burning Brakes
Joined: Apr 2004
Posts: 1,032
Likes: 197
From: Atoka, TN
What trans do you have/want?
The LS swap is the most reliable by far, modern tech, easier diagnostics, and no need for a specialized tuner or shop 300HP is easy thats just a cam swap, which is simple and quick to do with the motor out.
I'm currently working on getting AC in my LS swap project C4, I was going to swap to a Sanden compressor but bailed and instead went for a system recondition with a parralel flow condenser and beefier fans to pull more heat out of the insufficient fin area of any 134a condenser that will fit in a C4. The 85 apparently uses the 5 inch clutch on the R4 so you need a Cadillac R4 LS swap bracket, $110 from Ebay for a CNCed bracket with 2 rear supports, it should just barely clear the upper control arm. I also went for a shrouded aluminum radiator with 2 11" fans, my C4 had a leak in the pass side tank that caused it to drain the coolant whenever it ran. Should be frosty and the larger fans will help the LS stay cooler in the heat.
The LS swap is the most reliable by far, modern tech, easier diagnostics, and no need for a specialized tuner or shop 300HP is easy thats just a cam swap, which is simple and quick to do with the motor out.
I'm currently working on getting AC in my LS swap project C4, I was going to swap to a Sanden compressor but bailed and instead went for a system recondition with a parralel flow condenser and beefier fans to pull more heat out of the insufficient fin area of any 134a condenser that will fit in a C4. The 85 apparently uses the 5 inch clutch on the R4 so you need a Cadillac R4 LS swap bracket, $110 from Ebay for a CNCed bracket with 2 rear supports, it should just barely clear the upper control arm. I also went for a shrouded aluminum radiator with 2 11" fans, my C4 had a leak in the pass side tank that caused it to drain the coolant whenever it ran. Should be frosty and the larger fans will help the LS stay cooler in the heat.
Racer
Joined: Feb 2020
Posts: 483
Likes: 109
From: Fairfax, Virginia
The car is an auto with the 700r4. If I went with the LS I would probably go to the 4L60. The biggest issue with the LS swap is, while I have some time, I don’t want to invest the time to sort through what works. With ZZ6 or Ramjet, I can order one and when I am ready, spend the weekend completing the swap since the current trans and engine accessories will work. Was hoping someone build a spreadsheet of of part numbers of what exactly was needed for an LS swap.
Most people worry about the electrical side but there's 2 trains of thought, LS harness dominant, and integrating the C4 and LS harnesses together. LS harness dominant is by far the easiest, it relegates the pass side fuse panel to purely body/chassis functionality and uses the LS fuse/relay box for engine control, easiest to do but you've got to have the LS box. Integrating the 2 is the best looking but it means splitting the loom which intimidates a lot of people, I'm also working on making it possible to retain the pass side fuse panel but works gotten in the way of me getting to work on my car for the past three months or so.
Thread Starter
Burning Brakes
Joined: Apr 2004
Posts: 1,032
Likes: 197
From: Atoka, TN
Here is a decent article I found, on hood clearance, as I get closer to the end of the internet…
https://www.motortrend.com/how-to/ve...-flo-xt-intake
https://www.motortrend.com/how-to/ve...-flo-xt-intake
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Thread Starter
Burning Brakes
Joined: Apr 2004
Posts: 1,032
Likes: 197
From: Atoka, TN
I have no idea about the auto side of things but I have a cost accounting sheet of everything I've purchased to make the swap possible. Phobos above has an auto in his car and would probably know more about the auto swap and what it takes to make that work but I would be happy to go back through my CAW and add links and share it. In reality the motor drops right in with the swap plates, the difficult part is getting the driveline and exhaust right, that is oversimplifiying it though.
Most people worry about the electrical side but there's 2 trains of thought, LS harness dominant, and integrating the C4 and LS harnesses together. LS harness dominant is by far the easiest, it relegates the pass side fuse panel to purely body/chassis functionality and uses the LS fuse/relay box for engine control, easiest to do but you've got to have the LS box. Integrating the 2 is the best looking but it means splitting the loom which intimidates a lot of people, I'm also working on making it possible to retain the pass side fuse panel but works gotten in the way of me getting to work on my car for the past three months or so.
Most people worry about the electrical side but there's 2 trains of thought, LS harness dominant, and integrating the C4 and LS harnesses together. LS harness dominant is by far the easiest, it relegates the pass side fuse panel to purely body/chassis functionality and uses the LS fuse/relay box for engine control, easiest to do but you've got to have the LS box. Integrating the 2 is the best looking but it means splitting the loom which intimidates a lot of people, I'm also working on making it possible to retain the pass side fuse panel but works gotten in the way of me getting to work on my car for the past three months or so.
The hard parts are what concern me the most. Oil pan, engine accessories, what year(s) engine, the correct plates for engine placement, the 3 water inlet/outlets next to the right upper control arm, the correct ECM and trans controller…. For the wiring, I would hit the easy button and buy a custom harness so everything is fresh and I could eliminate as much of the stock harness as possible and only keep what is needed to power the body and interior accessories.
Last edited by cmashark; Jul 15, 2021 at 11:26 PM.
Thread Starter
Burning Brakes
Joined: Apr 2004
Posts: 1,032
Likes: 197
From: Atoka, TN
Hopefully this doesn’t violate any forum rules, but a couple brilliant vette guys in this thread…
http://www.corvetteforum.guru/module...post_id=165178
http://www.corvetteforum.guru/module...post_id=165178
Racer
Joined: Feb 2020
Posts: 483
Likes: 109
From: Fairfax, Virginia
The hard parts are what concern me the most. Oil pan, engine accessories, what year(s) engine, the correct plates for engine placement, the 3 water inlet/outlets next to the right upper control arm, the correct ECM and trans controller…. For the wiring, I would hit the easy button and buy a custom harness so everything is fresh and I could eliminate as much of the stock harness as possible and only keep what is needed to power the body and interior accessories.
Last edited by ThatOneKid; Jul 16, 2021 at 07:41 AM.