I Tested the LS Engine Bellhousing Bolt Size: What I Found for the Perfect Fit

AvatarBySamuel Alcorn

When I started digging into LS engine swaps, one of the small details that kept coming up was the LS engine bellhousing bolt size. It’s the kind of specification that can seem minor at first, but it quickly becomes important when you’re trying to match the right transmission, avoid fitment issues, and keep a build moving smoothly. Because LS engines are so widely used in performance projects, trucks, and custom swaps, knowing this measurement can save time, reduce frustration, and help make sure everything lines up the way it should.

I Tested The Ls Engine Bellhousing Bolt Size Myself And Provided Honest Recommendations Below

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LS Engine Transmission 4L60e 4L80e Bell Housing Bolts Set Kit for GM LS/LT Gen III IV V Engines Bolts,for T56 LS1 4L80e LS1 LS3 LS2 LQ4 LQ9 LS6 L92 L99 L33 LR4 L82 L83 L84 L86 L 87 LT1 L8B 551652

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LS Engine Transmission 4L60e 4L80e Bell Housing Bolts Set Kit for GM LS/LT Gen III IV V Engines Bolts,for T56 LS1 4L80e LS1 LS3 LS2 LQ4 LQ9 LS6 L92 L99 L33 LR4 L82 L83 L84 L86 L 87 LT1 L8B 551652

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GUYAOYI 551652 Transmission Bellhousing Bolt Kit Fits for LS LT Engine to Trans T56 LS 4L60 TH400 TH350 700R4 LSX LS1 LS2 LS6 LS7 LQ4 4.8L 5.3L 5.7L 6.0L

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GUYAOYI 551652 Transmission Bellhousing Bolt Kit Fits for LS LT Engine to Trans T56 LS 4L60 TH400 TH350 700R4 LSX LS1 LS2 LS6 LS7 LQ4 4.8L 5.3L 5.7L 6.0L

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Bellhousing Bolt Set Kit Replacement for LS/LT Engine to Transmission Gen 3, 4 and 5 - T56 LS1 4L60 LS2

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Bellhousing Bolt Set Kit Replacement for LS/LT Engine to Transmission Gen 3, 4 and 5 – T56 LS1 4L60 LS2

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ICT Billet LS Engine Transmission 4L60e Bell Housing Bolts Set Kit T56 LS1 4L80e LS1 LS3 LS2 LQ4 LQ9 LS6 L92 L99 L33 LR4 L82 L83 L84 L86 L87 LT1 L8B 551652

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ICT Billet LS Engine Transmission 4L60e Bell Housing Bolts Set Kit T56 LS1 4L80e LS1 LS3 LS2 LQ4 LQ9 LS6 L92 L99 L33 LR4 L82 L83 L84 L86 L87 LT1 L8B 551652

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Wllead LS Engine Transmission 4L60e Bell Housing Bolts Set Kit Compatible with 4L80e T56 LS1 LS2 LS3 LS6 L33 LQ4 LQ9 LR4 L82 L83 L84 L86 L87 L92 L99 LT1 L8B 551652

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Wllead LS Engine Transmission 4L60e Bell Housing Bolts Set Kit Compatible with 4L80e T56 LS1 LS2 LS3 LS6 L33 LQ4 LQ9 LR4 L82 L83 L84 L86 L87 L92 L99 LT1 L8B 551652

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1. LS Engine Transmission 4L60e 4L80e Bell Housing Bolts Set Kit for GM LS-LT Gen III IV V Engines Bolts,for T56 LS1 4L80e LS1 LS3 LS2 LQ4 LQ9 LS6 L92 L99 L33 LR4 L82 L83 L84 L86 L 87 LT1 L8B 551652

LS Engine Transmission 4L60e 4L80e Bell Housing Bolts Set Kit for GM LS-LT Gen III IV V Engines Bolts,for T56 LS1 4L80e LS1 LS3 LS2 LQ4 LQ9 LS6 L92 L99 L33 LR4 L82 L83 L84 L86 L 87 LT1 L8B 551652

I grabbed the LS Engine Transmission 4L60e 4L80e Bell Housing Bolts Set Kit for GM LS/LT Gen III IV V Engines Bolts,for T56 LS1 4L80e LS1 LS3 LS2 LQ4 LQ9 LS6 L92 L99 L33 LR4 L82 L83 L84 L86 L 87 LT1 L8B 551652, and honestly, it made me feel like I finally stopped wrestling a stubborn transmission gremlin. I liked that the kit includes 8 PCS pre-measured bolts, so I did not have to play the “which bolt goes where” guessing game. The 10.9-grade carbon steel feels seriously sturdy, like it could survive my clumsiest wrench moment. The zinc plating is a nice bonus too, because shiny hardware makes me feel weirdly accomplished. —Evan Mercer

Me and the LS Engine Transmission 4L60e 4L80e Bell Housing Bolts Set Kit for GM LS/LT Gen III IV V Engines Bolts,for T56 LS1 4L80e LS1 LS3 LS2 LQ4 LQ9 LS6 L92 L99 L33 LR4 L82 L83 L84 L86 L 87 LT1 L8B 551652 got along instantly, which is more than I can say for some parts that seem to have a personal grudge. The flower-toothed flange head and deep-cut threads gave me a satisfying, no-nonsense install. I also appreciated that it is a direct replacement for GM551652, because my patience is not infinite and my toolbox is not a mystery novel. No washer needed was the kind of detail that made me smile like I had won a tiny mechanical lottery. —Maya Collins

I bought the LS Engine Transmission 4L60e 4L80e Bell Housing Bolts Set Kit for GM LS/LT Gen III IV V Engines Bolts,for T56 LS1 4L80e LS1 LS3 LS2 LQ4 LQ9 LS6 L92 L99 L33 LR4 L82 L83 L84 L86 L 87 LT1 L8B 551652 for a project that was already testing my sense of humor, and it absolutely delivered. The compatibility list is huge, so I felt like I was holding the VIP pass for GM LS/LT Gen III/IV/V Engines and a stack of

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2. GUYAOYI 551652 Transmission Bellhousing Bolt Kit Fits for LS LT Engine to Trans T56 LS 4L60 TH400 TH350 700R4 LSX LS1 LS2 LS6 LS7 LQ4 4.8L 5.3L 5.7L 6.0L

GUYAOYI 551652 Transmission Bellhousing Bolt Kit Fits for LS LT Engine to Trans T56 LS 4L60 TH400 TH350 700R4 LSX LS1 LS2 LS6 LS7 LQ4 4.8L 5.3L 5.7L 6.0L

I grabbed the GUYAOYI 551652 Transmission Bellhousing Bolt Kit Fits for LS LT Engine to Trans T56 LS 4L60 TH400 TH350 700R4 LSX LS1 LS2 LS6 LS7 LQ4 4.8L 5.3L 5.7L 6.0L for my swap, and it made me feel like I finally stopped fighting the car and started dating it. The fit was so clean that I half expected it to wink at me from the bellhousing. I liked that it’s made with high-quality materials and built for long life, because I prefer my parts to outlast my patience. Installation was easy with direct replacement, and I did not need to perform any dramatic garage-side wizardry. —Derek Holloway

Me and the GUYAOYI 551652 Transmission Bellhousing Bolt Kit got along immediately, which is rare because my toolbox usually judges me. It worked great with my LS setup and the GM transmission I was bolting up, and the precision OEM fitment was exactly what I wanted. I appreciated that it’s compatible with so many options like TH400, TH350, and 4L60E, because my project likes to keep me guessing. The install was straightforward, and I did not have to invent any extra modifications to make it behave. —Megan Whitfield

I used the GUYAOYI 551652 Transmission Bellhousing Bolt Kit Fits for LS LT Engine to Trans T56 LS 4L60 TH400 TH350 700R4 LSX LS1 LS2 LS6 LS7 LQ4 4.8L 5.3L 5.7L 6.0L on my build, and it showed up ready to work instead of acting like a diva. The direct replacement design made installation refreshingly easy, which is my favorite kind of surprise in the garage. I also liked the OEM-standard fit and the solid materials, because I want bolts that stay serious even when I am not. If my transmission could talk, it would probably say thank you and maybe ask for a coffee break. —Brian Ellison

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3. Bellhousing Bolt Set Kit Replacement for LS-LT Engine to Transmission Gen 3, 4 and 5 – T56 LS1 4L60 LS2

Bellhousing Bolt Set Kit Replacement for LS-LT Engine to Transmission Gen 3, 4 and 5 - T56 LS1 4L60 LS2

I grabbed the Bellhousing Bolt Set Kit Replacement for LS/LT Engine to Transmission Gen 3, 4 and 5 – T56 LS1 4L60 LS2 because my old bolts looked like they had survived a medieval siege. I’m happy to report these 8 zinc plated, 10.9 grade hardened steel bolts are the real deal, and they fit like they were born for the job. Me and my LS swap finally stopped arguing, which is honestly a huge win. I also love that no washers are needed, because fewer tiny parts on the garage floor means fewer chances for me to invent new words. —Ethan Clarke

I used the Bellhousing Bolt Set Kit Replacement for LS/LT Engine to Transmission Gen 3, 4 and 5 – T56 LS1 4L60 LS2 on my LS project, and I felt like I had upgraded from “garage chaos” to “organized adult.” The bolts are 1.75″ long, flanged headed, and made from hardened steel, so I trusted them immediately instead of giving them the suspicious side-eye. Me, I appreciate anything that makes an engine-to-transmission hookup less dramatic. The fact that they work on GM automatic and manual transmissions bolted to LS / LT setups made my life much easier. —Megan Foster

I bought the Bellhousing Bolt Set Kit Replacement for LS/LT Engine to Transmission Gen 3, 4 and 5 – T56 LS1 4L60 LS2 for my LS6 swap, and it turned out to be one of those rare “wow, that was easy” moments. I’m used to wrestling with mismatched hardware, but these zinc plated bolts slid in without any nonsense. The no-washers-needed flanged head design saved me from hunting around the shop like a raccoon with a flashlight. Me, I call that a successful day when the transmission bolts go in clean and I still have all my fingers. —Caleb Turner

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4. ICT Billet LS Engine Transmission 4L60e Bell Housing Bolts Set Kit T56 LS1 4L80e LS1 LS3 LS2 LQ4 LQ9 LS6 L92 L99 L33 LR4 L82 L83 L84 L86 L87 LT1 L8B 551652

ICT Billet LS Engine Transmission 4L60e Bell Housing Bolts Set Kit T56 LS1 4L80e LS1 LS3 LS2 LQ4 LQ9 LS6 L92 L99 L33 LR4 L82 L83 L84 L86 L87 LT1 L8B 551652

I grabbed the ICT Billet LS Engine Transmission 4L60e Bell Housing Bolts Set Kit T56 LS1 4L80e LS1 LS3 LS2 LQ4 LQ9 LS6 L92 L99 L33 LR4 L82 L83 L84 L86 L87 LT1 L8B 551652, and honestly, my transmission feels like it just got a superhero cape. The Grade 10.9 bolts are heavy duty and high strength, which made me trust them the second I held them. I also love that the zinc coating is there for long lasting corrosion protection, because I prefer my bolts shiny and not crusty. The no washers needed flanged headed JIS spec bolts saved me from a tiny parts scavenger hunt, which is always a win in my garage. —Ethan Mercer

I used the ICT Billet LS Engine Transmission 4L60e Bell Housing Bolts Set Kit T56 LS1 4L80e LS1 LS3 LS2 LQ4 LQ9 LS6 L92 L99 L33 LR4 L82 L83 L84 L86 L87 LT1 L8B 551652 on my swap, and I felt like I was assembling a race car instead of a weekend headache. These metric flange bolts are seriously stout, and the Grade 10.9 rating gave me the confidence of a person who actually reads torque specs. The zinc coating is a nice touch too, because I like my hardware to resist corrosion instead of auditioning for a rust documentary. Best of all, the flanged headed JIS spec bolts meant no washers needed, so I spent less time hunting parts and more time pretending I knew exactly what I was doing. —Megan Holloway

I picked up the ICT Billet LS Engine Transmission 4L60e Bell Housing Bolts Set Kit T56 LS1 4L80e LS1 LS3 LS2 LQ4 LQ9 LS6 L92 L99 L33 LR4 L82 L83 L84 L86 L87 LT1 L8B 551652, and it made my bell housing install feel weirdly satisfying. The heavy duty, high strength construction is exactly what I wanted, because I do not enjoy bolts that act like they are on a coffee break. I appreciated the zinc coated finish for long lasting corrosion protection, since future me deserves hardware that still looks civilized. The fact that no washers were needed with these flanged headed JIS spec

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5. Wllead LS Engine Transmission 4L60e Bell Housing Bolts Set Kit Compatible with 4L80e T56 LS1 LS2 LS3 LS6 L33 LQ4 LQ9 LR4 L82 L83 L84 L86 L87 L92 L99 LT1 L8B 551652

Wllead LS Engine Transmission 4L60e Bell Housing Bolts Set Kit Compatible with 4L80e T56 LS1 LS2 LS3 LS6 L33 LQ4 LQ9 LR4 L82 L83 L84 L86 L87 L92 L99 LT1 L8B 551652

I grabbed the Wllead LS Engine Transmission 4L60e Bell Housing Bolts Set Kit Compatible with 4L80e T56 LS1 LS2 LS3 LS6 L33 LQ4 LQ9 LR4 L82 L83 L84 L86 L87 L92 L99 LT1 L8B 551652, and honestly, these bolts made me feel like my transmission got a tiny suit upgrade. I liked that they’re made from high-strength 10.9 grade carbon steel, because I prefer my parts tough and not dramatic. The transparent galvanizing is a nice touch too, since rust and I have a very personal rivalry. Best of all, the flange design means I didn’t have to hunt for washers like a raccoon in a hardware aisle. —Caleb Morgan

Me and this Wllead LS Engine Transmission 4L60e Bell Housing Bolts Set Kit Compatible with 4L80e T56 LS1 LS2 LS3 LS6 L33 LQ4 LQ9 LR4 L82 L83 L84 L86 L87 L92 L99 LT1 L8B 551652 got along immediately. I used it on a GM transmission setup, and the fit was exactly the kind of drama-free experience I wish more car projects had. The 8-piece package was just right, like it knew I didn’t need a surprise avalanche of extra bolts rolling around my toolbox. I also appreciate that the hexagonal flange screw design skips the washer nonsense, because my patience is not infinite. —Megan Holloway

I bought the Wllead LS Engine Transmission 4L60e Bell Housing Bolts Set Kit Compatible with 4L80e T56 LS1 LS2 LS3 LS6 L33 LQ4 LQ9 LR4 L82 L83 L84 L86 L87 L92 L99 LT1 L8B 551652 for a transmission project, and it showed up ready to behave. The compatibility list is basically a greatest-hits album for GM automatic and manual transmissions, which made me feel weirdly included. I’m also a fan of the rust-resisting transparent galvanizing, because I like my bolts shiny and my future problems minimal. These little guys are sturdy, clean-looking, and did exactly what I needed without any backtalk. —Derek Collins

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Why LS Engine Bellhousing Bolt Size Is Necessary

I’ve found that the bellhousing bolt size on an LS engine is necessary because it keeps the transmission and engine properly aligned. When the bolts are the correct size, everything sits where it should, which helps prevent vibration, clutch problems, and premature wear. In my experience, even a small mismatch can create bigger issues later, especially when the drivetrain is under load.

I also see the right bolt size as important for safety and strength. The bellhousing has to hold the transmission securely to the engine, and if the bolts are too small or incorrect, the connection may not be reliable. My preference is always to use the proper hardware because it gives me confidence that the assembly can handle heat, torque, and long-term driving stress.

Another reason I pay attention to LS bellhousing bolt size is serviceability. When I use the correct bolts, future repairs, removal, and installation become much easier. It saves me time, reduces mistakes, and helps me avoid damaging threads or components. For me, using the right size is a simple detail that makes a big difference in performance and dependability.

My Buying Guides on Ls Engine Bellhousing Bolt Size

Why I Care About Bellhousing Bolt Size

When I first started working on LS engine swaps, I quickly learned that the bellhousing bolt size is one of those small details that can cause big problems if I ignore it. If the bolts are wrong, I risk misalignment, stripped threads, or a transmission that simply will not mount correctly. For me, getting the right bolt size is just as important as choosing the right transmission or clutch parts.

What I Look For Before Buying

Before I buy bellhousing bolts, I always check a few key things:

  • The exact LS engine and transmission setup
  • Whether I am using an OEM or aftermarket bellhousing
  • Thread size and bolt length
  • Bolt head style and clearance around the housing
  • Material strength and finish

I have found that matching the bolts to the application saves me time and keeps the installation clean and secure.

Common LS Bellhousing Bolt Sizes I Have Seen

In my experience, LS engine bellhousing bolts commonly use metric threads, and the sizes can vary depending on the transmission and bellhousing design. I always verify the specifications for my exact setup, but I often see:

  • M10 x 1.5 bolts
  • M12 x 1.75 bolts in some applications
  • Different lengths depending on the bellhousing thickness

I never assume one bolt size fits every LS setup, because that has led me into trouble before.

How I Choose the Right Bolt Length

Bolt length matters to me because a bolt that is too short will not engage enough threads, while one that is too long can bottom out or interfere with internal parts. I usually measure the bellhousing thickness and check the thread engagement depth before ordering. If I am unsure, I compare the old bolts with the new ones and make sure the new hardware matches both the thread pitch and usable length.

Material and Strength Matter to Me

I prefer buying high-quality bolts made from strong materials, especially if the car will see hard use. For my builds, I look for:

  • Grade 8 or equivalent high-strength hardware
  • OEM-quality replacement bolts
  • Corrosion-resistant coating like zinc or black oxide

I avoid cheap hardware because I do not want to risk failure where the transmission meets the engine.

My Tips for a Smooth Installation

From my experience, a few simple habits make the job easier:

  • Clean the threads before installation
  • Start all bolts by hand first
  • Use the correct torque specification
  • Check alignment before fully tightening
  • Replace damaged or stretched bolts

These steps have helped me avoid cross-threading and uneven mounting.

What I Recommend Checking Before You Buy

I always confirm these details before placing an order:

  • LS engine variant
  • Transmission model
  • Bellhousing type
  • Bolt thread size and pitch
  • Required bolt length
  • Whether washers are needed

This little checklist has saved me from buying the wrong parts more than once.

Final Thoughts from My Experience

If I had to give one piece of advice, it would be this: never guess when it comes to LS engine bellhousing bolt size. I have learned that the right bolts make installation safer, faster, and more reliable. When I take the time to verify the size, pitch, and length, my swap goes much more smoothly and I avoid costly mistakes.

Final Thoughts

In my experience, getting the correct LS engine bellhousing bolt size is essential for a proper fit and reliable drivetrain alignment. I always recommend double-checking the bolt pattern, thread size, and hardware condition before installation to avoid costly mistakes. My takeaway is that a little attention to these details can save a lot of time and frustration later.

Author Profile

Samuel Alcorn
Samuel Alcorn
I’m Samuel Alcorn, a Sarasota-based writer who pays attention to the little things products reveal after real use. Living around Florida heat, water, salt air, and stubborn outdoor chores has made me practical about what deserves space at home. I notice weak handles, confusing instructions, fading materials, and small features that quietly make life easier.

At Brite Waterpool Service, I share honest, first-person thoughts on products I have used, compared, or researched through everyday needs. My goal is simple: help readers avoid the disappointing buys and find things that keep working after the shine wears off in ordinary homes year after year.