Trying to figure out an LS swap

I have a 1978 caprice two-door landau with the rare skyroof. I've been racking my brain with the possibilities that can go with an LS swap with our B-bodies. I'm an enthusiast and a novice and I need guidance. I want a 5.3 ls motor however I'm not sure with what transmission I should go with along with and what adapters to make everything fit and crossmember around whatever transmission I go with. So I'm trying to figure out what to get and how I make it all fit. please anyone chime in... especially moderators.

A Gen III/ IV "LS" Swap can be broken down to the following in short:

Engine Mounts:

1. Stock bell housing location, 1" forward, 1" back or anything in between depending on the mounts you choose.

- Oil pan selection
- Drive shaft length

Transmission Crossmember:

1. There are aftermarket companies out there that make products for the Automatic 4L60/65/70E, 6L80/90E, and Manual T56, TR6060 etc.
2. Most of the aftermarket will allow for provisions for a dual exhaust crossmember.

Engine:

1. Gen III w/ 24x reluctor wheel signal, Drive By Cable (DBC) (411 ECM)
2. Gen IV w/ 58x reluctor wheel signal, Drive By Wire DBW) (E38 or E67 ECM)

- The engine may have Active Fuel Management (AFM)/ Displacement on Demand (DoD) or Variable Valve Timing (VVT), and quite possibly a newer Gen IV may have both.
**No cam upgrades for AFM/ Dod equipped engines (there are AFM/DoD delete kits available).
***Cam upgrades available for VVT engines with the use of a camshaft phaser limiter.
- Most engine mounts available should allow for stock hood clearance with the truck style intake, at least without the plastic engine cover.

Transmission:

1. 4L60/65/70E series transmissions should fit under the GM B-Body with no modifications as they are pretty much the same size as the 200 and 700 older transmissions.
2. 6L80/90E series transmissions will work, but the transmission tunnel would need to be enlarged.

-When purchasing a transmission crossmember you will need to know what transmission you will be running.
-There are some slight changes in the later model 4L60/65/70E series transmissions, and you will need to know what year it is if you are using an aftermarket engine wire harness.

Oil Pan:

1. Mast Motorsports LS Conversions Pan
2. Holley 302-1 and 302-2 Pan
3. GM LH8 Oil Pan

*The above are most popular.

- Notching the frame is pretty much a thing of the past with all the oil pan options available now for all these types of swaps.
- The above mentioned oil pans are still different shapes and dimensions, some will hang lower than other and all depends on the engine mounts you choose, meaning, still do some research.

Engine Wire Harness:

1. Rework existing engine harness if you get a full pull out engine from a salvage yard.
2. Speartech, PSI Conversion are most popular with a plethora of options including emissions or no emissions, etc.

- Some of the above will sell whole packages, which include the ECM, TCM (if required), Pedal, Engine Wire Harness etc.

Front Accessory Drive:

1. Some forward mounting engine mounts may allow for the use of stock truck accessories.
2. Aftermarket is all over this if you can't use low mount A/C and Alternator relocation etc., Dirty Dingo, Kwik, Holley, GMPP and a bunch of others and you can spend more than the whole swap on this section if you want Billet Aluminum.

Fuel:

1. Carb
2. EFI

- EFI will require an external fuel pump or an intake fuel pump.
- EFI you may be able to use a tank from a 1986-1990 TBI (has a simple baffle/ bowl for EFI to reduce fuel starvation), Spectra Premium or Dorman should have these.
- EFI Fuel sending unit from same model witht he TBI engine would work. You can either buy the fuel sending unit with or without the fuel pump as you will need one that can produce at least 60 psi.
- EFI Return or Returnless. All are return fuel systems, but it depends where the engine does it, either at the fuel rail on the engine (Return) or at the fuel pressure regulator/ filter (Returnless) usually installed near the fuel tank. Either way you will need a fuel pressure regulator/ filter to regulate fuel to 58psi.

Fuel Lines:

- If you are replacing fuel lines with any sort of flexible type, make sure it is PTFE lines and PTFE with Conductive Core is even better which PTFE material all super low permeation rates.

Cooling:

- Many have used stock radiator with decent results.
- Aluminum replacement radiator if you want to do big HP.
- LS Swap aluminum radiator will be the type with a built in steam port and most likely the inlet and outlet on the passenger side of the radiator. If using automatic transmission, be sure it includes a transmissions cooler or you will have to mount an external type.
- Electric fans, there are many companies that produce bolt in, clip in etc. and junkyard versions for F Body etc.

Exhaust:

- Make sure the headers you use will work with the engine mounts you choose.
- Custom exhaust shop or other.

Xtreme Thunder wrote:A Gen III/ IV "LS" Swap can be broken down to the following in short:

Engine Mounts:

1. Stock bell housing location, 1" forward, 1" back or anything in between depending on the mounts you choose.

- Oil pan selection
- Drive shaft length

Transmission Crossmember:

1. There are aftermarket companies out there that make products for the Automatic 4L60/65/70E, 6L80/90E, and Manual T56, TR6060 etc.
2. Most of the aftermarket will allow for provisions for a dual exhaust crossmember.

Engine:

1. Gen III w/ 24x reluctor wheel signal, Drive By Cable (DBC) (411 ECM)
2. Gen IV w/ 58x reluctor wheel signal, Drive By Wire DBW) (E38 or E67 ECM)

- The engine may have Active Fuel Management (AFM)/ Displacement on Demand (DoD) or Variable Valve Timing (VVT), and quite possibly a newer Gen IV may have both.
**No cam upgrades for AFM/ Dod equipped engines (there are AFM/DoD delete kits available).
***Cam upgrades available for VVT engines with the use of a camshaft phaser limiter.
- Most engine mounts available should allow for stock hood clearance with the truck style intake, at least without the plastic engine cover.

Transmission:

1. 4L60/65/70E series transmissions should fit under the GM B-Body with no modifications as they are pretty much the same size as the 200 and 700 older transmissions.
2. 6L80/90E series transmissions will work, but the transmission tunnel would need to be enlarged.

-When purchasing a transmission crossmember you will need to know what transmission you will be running.
-There are some slight changes in the later model 4L60/65/70E series transmissions, and you will need to know what year it is if you are using an aftermarket engine wire harness.

Oil Pan:

1. Mast Motorsports LS Conversions Pan
2. Holley 302-1 and 302-2 Pan
3. GM LH8 Oil Pan

*The above are most popular.

- Notching the frame is pretty much a thing of the past with all the oil pan options available now for all these types of swaps.
- The above mentioned oil pans are still different shapes and dimensions, some will hang lower than other and all depends on the engine mounts you choose, meaning, still do some research.

Engine Wire Harness:

1. Rework existing engine harness if you get a full pull out engine from a salvage yard.
2. Speartech, PSI Conversion are most popular with a plethora of options including emissions or no emissions, etc.  

- Some of the above will sell whole packages, which include the ECM, TCM (if required), Pedal, Engine Wire Harness etc.

Front Accessory Drive:

1. Some forward mounting engine mounts may allow for the use of stock truck accessories.
2. Aftermarket is all over this if you can't use low mount A/C and Alternator relocation etc., Dirty Dingo, Kwik, Holley, GMPP and a bunch of others and you can spend more than the whole swap on this section if you want Billet Aluminum.

Fuel:

1. Carb
2. EFI

- EFI will require an external fuel pump or an intake fuel pump.
- EFI you may be able to use a tank from a 1986-1990 TBI (has a simple baffle/ bowl for EFI to reduce fuel starvation), Spectra Premium or Dorman should have these.
- EFI Fuel sending unit from same model witht he TBI engine would work. You can either buy the fuel sending unit with or without the fuel pump as you will need one that can produce at least 60 psi.
- EFI Return or Returnless.  All are return fuel systems, but it depends where the engine does it, either at the fuel rail on the engine (Return) or at the fuel pressure regulator/ filter (Returnless) usually installed near the fuel tank.  Either way you will need a fuel pressure regulator/ filter to regulate fuel to 58psi.

Fuel Lines:

- If you are replacing fuel lines with any sort of flexible type, make sure it is PTFE lines and PTFE with Conductive Core is even better which PTFE material all super low permeation rates.

Cooling:

- Many have used stock radiator with decent results.
- Aluminum replacement radiator if you want to do big HP.
- LS Swap aluminum radiator will be the type with a built in steam port and most likely the inlet and outlet on the passenger side of the radiator.  If using automatic transmission, be sure it includes a transmissions cooler or you will have to mount an external type.
- Electric fans, there are many companies that produce bolt in, clip in etc. and junkyard versions for F Body etc.

Exhaust:

- Make sure the headers you use will work with the engine mounts you choose.
- Custom exhaust shop or other.

dude, thanks. you gave me a blue print to get this done. much appreciation.

No problem, check out YouTube and type any combination of Caprice and LS, 5.3L, 5.3 etc you can think. There are some very recent ones doing the swap in their 80's Caprice.

I'd use the list as a starting guide to get you going more than an exact Blueprint as I am sure I forgot some items, like the plumbing hoses for heat, transmission lines and power steering. In addition to the fuel lines I mentioned, make sure you use the manufacturer's hose ends as they are usually product specific.

In addition, if you want your stock Speedo to work check out Dakota Digital as your existing Speedo is mechanical driven and new electronic transmissions/ and engine ECM use a VSS signal. If you go Gen IV, and have cruise control and want it functioning, Dakota Digital has a solution for that too.

Can you tell what I have going on in my garage soon?! Haha!

Xtreme Thunder wrote:No problem, check out YouTube and type any combination of Caprice and LS, 5.3L, 5.3 etc you can think. There are some very recent ones doing the swap in their 80's Caprice.

I'd use the list as a starting guide to get you going more than an exact Blueprint as I am sure I forgot some items, like the plumbing hoses for heat, transmission lines and power steering. In addition to the fuel lines I mentioned, make sure you use the manufacturer's hose ends as they are usually product specific.

In addition, if you want your stock Speedo to work check out Dakota Digital as your existing Speedo is mechanical driven and new electronic transmissions/ and engine ECM use a VSS signal. If you go Gen IV, and have cruise control and want it functioning, Dakota Digital has a solution for that too.

Can you tell what I have going on in my garage soon?! Haha!

actually, bro, all my gauges are fucked at the moment. My speedo doesn't work, signal lights don't work, I use my wiper and different lights turn on, etc... that's been a headache. I took it to a electric shop and the guy said he couldn't fix it. I'm thinking of taking it to a gauge/ speedo shop or just getting the dakota digital

You can use any GM transmission with an Gen  III or IV engine. This was done not by the aftermarket but

by GM themselves to fit the 4l80e .

Here's clip from HR article about it.

"Gen I Automatics Behind Gen III/IV Engines
The same mismatch between the 0.400-inch-shorter crank flange position relative to the bellhousing is what makes matching up a typical TH350/TH400/200-4R or early 700-R4 to a Gen III/IV engine a bit different. The beauty of this swap is most of the mismatch situations can be solved with the use of a simple steel adapter. GM actually faced an identical situation when bolting the 4L80E automatics behind 5.3L and 6.0L engines in larger trucks. The 4L80E automatic is basically a Gen I-style automatic, which required an adapter. To compensate, GM created a simple steel spacer that bolts on the Gen III/IV crank flange and combines with a flat flexplate. All this information is published in the GM Performance Parts LS1 engine swapping performance pamphlet. The adapter and flat flexplate, along with longer metric bolts, are intended to be used together and will allow you to bolt any Powerglide, TH350, TH400, 700-R4, or 200-4R automatic to a Gen III/IV version engine. The part numbers for these pieces can be found in the parts list at the end of this story."

The only issue aside from the steel adapter is the bolt holes need to be manually matched to it with a die grinder etc to

elongate them to fit.

As to your Speedometer have you replaced the cable they are only $10 or so and can be changed in 5 minutes.

Myloth wrote:You can use any GM transmission with an Gen  III or IV engine.

Cannot use BOP-C GM transmissions, only chevy bellhousing transmissions will bolt up