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S&S 100" Sidewinder Big Bore Kit

Item: 359371

$1395.86 – $1435.46

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S&S 100" Sidewinder Big Bore Kit


S&S 4" big bore cylinder and piston kit boosts Twin Cam 88 Harley-Davidson big twin engines to 100" displacement. This kit does not require any machining, rebalancing or engine removal, and includes just about everything you'll need to complete the installation. These are biggest cylinder bore that can be installed in a stock crankcase without machining!

  • Bolt-in kit requires no machining, balancing, or splitting the crankcases
  • Converts Twin Cam 88 engine to 100 cubic inches of power
  • Complete kit includes cylinders, pistons, gaskets, and instructions
  • Powder coated cylinder finish matches stock finish of your bike
  • Made in the USA
Specification Details
Bore 4 in.
Color Varies (make selection above)
Compression Ratio 10.5:1
Country of Origin USA
Displacement 100 CI
Engine Type Twin Cam 88
Finish Powder Coated
Material Aluminum
Stroke 4 in.

Vehicle Fitment


Fitment is guaranteed or your money back plus free return shipping.
Don’t waste time installing a product that doesn't fit. We worked hard ensuring that this product is an exact fit on the vehicles listed below.

Harley Davidson
  • FLHR Road King 2000-2006
  • FLHRCI Road King Classic 2000-2006
  • FLHRI Road King 2000-2006
  • FLHRS Road King Custom 2004-2006
  • FLHRSI Road King Custom 2004-2006
  • FLHT Electra Glide Standard 2000-2006
  • FLHTC Electra Glide Classic 2000-2005
  • FLHTCI Electra Glide Classic 2000-2006
  • FLHTCU Ultra Classic Electra Glide 2000-2006
  • FLHTCUI Ultra Classic Electra Glide 2000-2006
  • FLHTI Electra Glide Standard 2003-2006
  • FLHX Street Glide 2006
  • FLHXI Street Glide 2006
  • FLST Heritage Softail 2006
  • FLSTC Heritage Softail Classic 2000-2006
  • FLSTCI Heritage Softail Classic 2001-2006
  • FLSTF Softail Fat Boy 2000-2006
  • FLSTFI Softail Fat Boy 2001-2006
  • FLSTI Heritage Softail 2006
  • FLSTN Softail Deluxe 2005-2006
  • FLSTNI Softail Deluxe 2005-2006
  • FLSTS Heritage Springer Softail 2000-2003
  • FLSTSC Softail Springer Classic 2005-2006
  • FLSTSCI Softail Springer Classic 2005-2006
  • FLSTSI Heritage Springer Softail 2001-2003
  • FLTR Road Glide 2000-2004
  • FLTRI Road Glide 2000-2006
  • FXD Dyna Super Glide 2000-2005
  • FXDBI Dyna Street Bob 2006
  • FXDC Dyna Super Glide Custom 2005
  • FXDCI Dyna Super Glide Custom 2005-2006
  • FXDI Dyna Super Glide 2004-2006
  • FXDI35 35th Anniversary Dyna Super Glide 2006
  • FXDL Dyna Low Rider 2000-2005
  • FXDLI Dyna Low Rider 2004-2006
  • FXDS-CONV Dyna Convertible 2000
  • FXDWG Dyna Wide Glide 2000-2005
  • FXDWGI Dyna Wide Glide 2004-2006
  • FXDX Dyna Super Glide Sport 2000-2005
  • FXDXI Dyna Super Glide Sport 2004-2005
  • FXDXT Dyna Super Glide T-Sport 2001-2003
  • FXST Softail Standard 2000-2006
  • FXSTB Softail Night Train 2000-2006
  • FXSTBI Softail Night Train 2001-2006
  • FXSTD Softail Deuce 2000-2006
  • FXSTDI Softail Deuce 2001-2006
  • FXSTI Softail Standard 2001-2006
  • FXSTS Springer Softail 2000-2006
  • FXSTSI Springer Softail 2001-2006

Customer Reviews

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Questions & Answers

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What types of pistons come with the kit are they forged

I'm in the middle of a build and have the option to run a nitro use kit and was wondering if the pistons the kit supply's are forged or not

Yes, these 100" big bore kits from S&S come with forged pistons.

By Tom
Answer Question

Can I keep my 509 cams with the 100 inch kit or would the 585 be a better option ?

I'm looking to do the 100 inch kit but I have 509 cams in my tc 88. Should I change to the 585 or keep my 509 cams ?

No, there's no requirement to change cams just because you're installing this Harley-Davidson big bore kit. That cam will be more than up to the task of helping your bike achieve good power output!

By Tom
Answer Question

Would the S&S cam be a good cam for The Sidewinder SMS Big Bore 100?

Yes - absolutely. When it comes to S&S engine parts, they work really well together since they're all developed and tested by the same people at the same company. We have, literally, thousands upon thousands of very happy S&S customers at PartsGiant.com!

By Tom
Answer Question

Are the pistons ready to go in the cylinders or do the cylinders need to be bored to match the pistons?

Yes, the cylinders are already matched to the pistons included in this kit.

By Andy
Answer Question

Would the 585ce cam be a good match for this kit i got a 2003 roadking?

Yes, the 585 cams would be a great match for the 100" Big Bore Kit on that 2003 FLHR Roadking.

By Andy
Answer Question

Do u need to upgrade stock oil pump?

S&S doesn't state that it needs to be replaced or upgraded but wouldn't be a bad idea when doing any kind of high performance engine modifications.

By Andy
Answer Question

Do I need to change my injectors and throttle body on a 2005 Softail Standard when installing the hundred inch kit

S&S does not state that you would need to change the injectors or throttle body for installation of this kit.

By Andy
Answer Question

Do you have to have high mechanical capabilities to do this installation?

It is an involved project for the average Joe to take on, especially with the amount of money these kits cost. We suggest having a trained professional take care of the installation of a kit like this.

By Andy
Answer Question

i have an 06 night train, using this kit do i have to upgrade the cams and switch to 6 speed transmission?

It is not necessary to upgrade either of those parts. If you want to get the most out of this kit, I would suggest going with a set of cams as well.

By Andy
Answer Question

do the cylinders have a steel liner?

Sidewinder big bore kits come with ductile cast iron liners fitted in cast aluminum jugs.

By Staff
Answer Question

Can i use ported heads with this kit or do i have to use stock heads

Absolutely - with this kit, you can use any cylinder head configuration that would otherwise work with the stock cylinders. This allows you plenty of flexibility for your big bore build.

By Staff
Answer Question

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