AngeliCar: 1967 Impala LS Swap – Part 1: The basics

So, you have a ’67 Impala, and you picked up an LS for a bargain. Now what?

Before we get started, I want it to be known what I write will not be an extensive write-up for all LS Swaps. There are fantastic resources available online that go into details about different engines, the electrical systems, programming the ECU, etc. I won’t be going that in depth.

What I will be writing about is getting such a system to fit into a 1967 Chevy Impala. What parts I used, why I chose certain parts over others, what compatibility issues I faced, and then what I had to do to get those parts to fit.

Whilst nothing about putting an LS into a 1967 Impala is overly difficult, the process is somewhat extensive. Unlike swapping that tired 327 for a new crate 350, which requires nothing but changing out the engine – or even swapping out the old SBC for a Big Block, which generally only requires different engine mounts, a bigger radiator, intake/carby, and headers/exhaust. That may be overly-simplified an explanation, but everything is essentially plug and play. You can take something off one Impala, and put it into another.

An LS swap requires a new system. Let me explain.

Not only are you updating the engine and transmission, you need to upgrade the following:

Electronics – There’s no way around it. You will need to fit an ECU. You will need to acquire the main engine harness and computer that came with your engine, and have it modified to suit your application. You can by an aftermarket harness with computer.

Fuel System – You will now require an electronic fuel pump. This will require inserting a new pump system into your existing fuel tank (recommended), or installing an inline pump/filter system (attaches to the chassis). You’ll also need to add a fuel pressure regulator.

Cooling System – The radiator needs to be cooled. An LS utilises a serpentine belt system, which means no more fan on the front of the engine – so you need to add electronically controlled thermo fans to the radiator.

Exhaust – You are going to require new exhaust manifolds/extractors, and most likely, an entire exhaust system. Your old small block headers won’t mount, and there are only one or two stock GM exhaust manifolds – found on certain 6.0l and 6.2l applications – that will fit in your 67.

Accessory Drive – The front accessories – Alternator, Air-con compressor, etc – in their stock location (bottom) hit your front cross-member. You need to either purchase an aftermarket bracket kit (Holley, Kwik Performance, etc) which relocates them to the top of the engine, or, you need to make significant modifications to your cross-member. That means cutting and welding.

Instruments – Your old idiot lights on the dash will no longer be adequate (were they ever?). You will need, at minimum, a fuel pressure gauge. Adding water temp, oil pressure, and voltage gauges are highly advised.

As you can see, things start to add up. While most, if not all, can be sorted with readily available off the shelf aftermarket parts, it’s still a significant amount of work.

On top of all that, there a still some things you need to change/buy to install these items.

  • New engine mount adapters to mate the LS to the factory mounts.
  • Oil Pan with a rear sump that clears the cross-member and steering linkages – which also needs a new oil pickup (Holley sells a pan and pickup kit).
  • Air intake system – pipe, air filter, bends, clamps.
  • New fuel line, plus new AN-style fittings. Whichever fuel pump you decide on – internal or external – expect to spend a couple hundred dollars on AN fittings alone.
  • O2 sensors for your exhaust.
  • If you’re using an older transmission (pre-LS), you will need a new flexplate that will adapt your trans to the LS, as well as a torque converter.
  • Depending on the transmission used, you will likely have to move the trans cross-member.

All of the above covers the basics. There are still different options depending on whether you’re using the stock intake, or switching to an aftermarket setup – some people don’t like the stock intake on the 5.3’s etc.

I will cover each phase in its own specific post, and first up, will be the engine & trans.

Cheers.

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Comments
4 Responses to “AngeliCar: 1967 Impala LS Swap – Part 1: The basics”
  1. Jeff says:

    Did you just use a 67 factory type radiator with fans? Or is that another system?

  2. Jeff Remy says:

    What part number are your hooker exhaust manifolds?

    • 8501HKR. There is also 8502HKR which has a 2.5″ outlet.

      I didn’t end up using them because of fitment issues (my car is right-hand drive). Be mindful that being cast iron, if you have fitment issues they can’t be modified. If clearance is an issue, you’ll have to use something else.

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