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What's the best bang-for-buck intake manifold for a stock-motor LS1?

The stock LS1 intake is the weak link among factory LS intakes, so almost any factory upgrade helps.

Last updated

  • LS6 intake (or Dorman's copy): long a quick upgrade worth 15-plus hp on a hot-rodded LS1. GM stopped making it; Dorman's replacement made nearly the same power as the original in a dyno test.
  • TBSS intake: the best-performing factory cathedral-port intake, but tall — often a no-go on low-hood applications.
  • Aftermarket short-runner intakes add top-end power but can give up torque through much of the curve. Match the intake to the rpm range you'll use.

The gains are smaller on a stock engine than on a modified one: the more the rest of the engine flows, the more a better intake adds.

What we recommend

Our go-to for a stock-motor LS1 is a used LS6 intake. Paired with a ported throttle body, it's a noticeable improvement (aim for around 15 hp), it stays adequate even with a mild cam, and used ones are safe to buy. We'd save the FAST 102 for a car that mostly sees the track.

Check this first:

  • Used intake is free of cracks and damaged gasket surfaces
  • Retune after the swap

Based on what we've seen work across our own builds, our friends' builds and the wider LS community, reviewed by our lead shop tuner (over 20 years of LS and LT tuning experience). Every combination is different, so use at your own risk and check our safe tuning limits before any wide-open pass.

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Check this first

  1. Used intake is free of cracks and damaged gasket surfaces
  2. Retune after the swap

Try this, then this

  1. Used LS6 intake + retune
  2. Add ported throttle body
  3. FAST only if the car becomes a track build

How you know it's fixed

  • Seat-of-the-pants and dyno/trap improvement around 10-15 hp over the LS1 intake

Still not fixed?

  • If gains are small, the car likely had an LS6 intake already (2001+ cars) — check the part number

Time and cost: Used LS6 intakes are the cheapest real horsepower you can bolt on

Is a Dorman LS6 intake as good as a real GM LS6 intake?
What we recommend

It's close: the Dorman LS6-style intake makes nearly the same power as a genuine LS6, typically only a few hp off. If you want a Dorman part, we recommend the Dorman LS2 intake instead: it uses a 90mm throttle body, flows slightly better than a factory LS6, and was $408 new from Summit in 2019. It needs the LS6 coolant crossover and rear block-offs to work on an LS1. A genuine used LS6 intake is still a big step up from an LS1, and around $350 was a fair price in 2019. Avoid cheap eBay knockoff intakes.

Check this first:

  • If running the Dorman LS2 intake, source the LS6 coolant crossover and rear block-offs
  • Plan for a 90mm throttle body with the LS2-style intake

Check this first

  1. If running the Dorman LS2 intake, source the LS6 coolant crossover and rear block-offs
  2. Plan for a 90mm throttle body with the LS2-style intake

Try this, then this

  1. Genuine used LS6 (best)
  2. Dorman LS6 (a few hp off, new and available)
  3. Dorman LS2 if you want the 90mm throttle body

How you know it's fixed

  • Intake installed with correct coolant lines, no leaks, expected gains

Still not fixed?

  • If buying used, check for cracks and damaged gasket surfaces before paying

Time and cost: Used LS6 ~$350 (2019); Dorman LS2 was $408 new (2019); Dorman LS6 priced in between

What's a used LS6 intake actually worth these days?
What we recommend

A complete used LS6 intake setup is worth about $450 as of June 2026, assuming the MAP sensor tab is intact. Good used ones sold around $350 in 2019, so prices have crept up with scarcity. We recommend checking the MAP tab, throttle body flange and vacuum ports for cracks or repairs before paying full price. Also budget for a coolant crossover and rear block-off kit if your engine doesn't have the LS6 steam pipe setup.

Check this first:

  • MAP sensor tab intact
  • Throttle body flange and vacuum ports free of cracks or repairs
  • Whether your engine needs a steam pipe crossover and block-off kit

Check this first

  1. Verify the intake is a genuine LS6 (casting numbers, no EGR port)
  2. Have the LS6 steam pipe on hand

Try this, then this

  1. Used LS6 (best value)
  2. Dorman LS6 (new alternative)
  3. FAST if heads and cam are planned

How you know it's fixed

  • Intake installed, no leaks, tune updated

Still not fixed?

  • If buying used, check for cracks before paying

Time and cost: ~$450 used (mid-2026); Dorman new runs more

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