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Long Block Kits (Unassembled)
Pontiac V8 Long Block Kits (Unassembled)
Machined, Matched, Yours to Bolt Together — Long Block Kits (Unassembled) for Pontiac V8s
A Long Block Kit (LBK) is a Short Block Kit plus cylinder heads — the prepped block, the balanced rotating assembly and the heads that go on top of it. Unassembled means the parts arrive machined, matched and ready to bolt together by you or your engine shop, which is how a lot of Pontiac guys prefer to do it.
Butler builds these around 350, 389, 400, 428 and 455 Pontiac castings and the aftermarket IAII block, with strokes from 3.750" to 4.500" and displacements running from 395 cubic inches out past 500. Every block goes through the Butler Process before anything is fitted to it.
Browse Long Block Kits (Unassembled) Products
Items 1-21 of 21
Description:
Customized Butler Performance Short Block Kit
Choose Bore Size
3.750" Stroke
Great budget friendly package tailored to you
Rated for up to 500hp...More Details »
Item #: BP-SB-Kit-400-3750-557
Condition:
New
Please Call for Availability
Now ships in 15-17 Weeks!!! (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Choose Bore Size
4.000" Stroke
Great budget friendly package tailored to you
Rated for up to 500hp...More Details »
Item #: BP-SB-Kit-400-4000-557
Condition:
New
Please Call for Availability
15-17 weeks (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Choose Bore Size
3.750" Stroke
Great budget friendly package tailored to you
All short blocks...More Details »
Item #: BP-SB-Kit-350-3750
Condition:
New
Please Call for Availability
15-17 weeks (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Choose Bore Size
4.000" Stroke
All short blocks undergo the "Butler Process"
Item #: BP-SB-Kit-350-4000
Condition:
New
Please Call for Availability
15-17 weeks (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Choose Bore Size
4.250" Stroke
All short blocks undergo the "Butler Process"
Item #: BP-SB-Kit-350-4250
Condition:
New
Please Call for Availability
15-17 weeks (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
3.750" Stroke
Great budget friendly package tailored to you
All short blocks undergo the "Butler Process"
Item #: BP-SB-Kit-389-3750
Condition:
New
Please Call for Availability
15-17 weeks (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
4.0000" Stroke
Great budget friendly package tailored to you
All short blocks undergo the "Butler Process"
Item #: BP-SB-Kit-389-4000
Condition:
New
Please Call for Availability
15-17 weeks (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
4.250" Stroke
Great budget friendly package tailored to you
All short blocks undergo the "Butler Process"
Item #: BP-SB-Kit-389-4250
Condition:
New
Please Call for Availability
15-17 weeks (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Choose Bore Size
3.750" Stroke
Great budget friendly package tailored to you
All short blocks...More Details »
Item #: BP-SB-Kit-400-3750
Condition:
New
Please Call for Availability
Now ships in 15-17 Weeks!!! (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Option to send us your block
Choose Bore Size, Stroke, Crank, & Rod
4.000" Stroke
Create a custom...More Details »
Item #: BP-SB-Kit-400-4000
Condition:
New
Please Call for Availability
15-17 weeks (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Option to send us your block
Choose Bore Size, Stroke, Crank, & Rod
4.210" Stroke
Create a custom...More Details »
Item #: BP-SB-Kit-400-4210
Condition:
New
Please Call for Availability
15-17 weeks (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Option to send us your block
Choose Bore Size, Stroke, Crank, & Rod
4.250" Stroke
Create a custom...More Details »
Item #: BP-SB-Kit-400-4250
Condition:
New
Please Call for Availability
Now ships in 15-17 Weeks!!! (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Option to send us your block
Choose Bore Size, Stroke, Crank, & Rod
4.350" Stroke
Create a custom...More Details »
Item #: BP-SB-Kit-400-4375
Condition:
New
Please Call for Availability
15-17 weeks (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Option to send us your block
Choose Bore Size, Stroke, Crank, & Rod
4.500" Stroke
Create a custom...More Details »
Item #: BP-SB-Kit-400-4500
Condition:
New
Please Call for Availability
15-17 weeks (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Option to send us your block
Choose Bore Size, Stroke, Crank, & Rod
4.210" Stroke
Create a custom...More Details »
Item #: BP-SB-Kit-428-4210
Condition:
New
Please Call for Availability
15-17 weeks (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Option to send us your block
Choose Bore Size, Stroke, Crank, & Rod
Choose 4.250" Stroke
Create a...More Details »
Item #: BP-SB-Kit-428-4250
Condition:
New
Please Call for Availability
Now ships in 15-17 Weeks!!! (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Option to send us your block
Choose Bore Size, Stroke, Crank, & Rod
Choose 4.500" Stroke
Create a...More Details »
Item #: BP-SB-Kit-428-4500
Condition:
New
Please Call for Availability
15-17 weeks (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Option to send us your block
Choose Bore Size, Stroke, Crank, & Rod
Choose 4.210" Stroke
Create a...More Details »
Item #: BP-SB-Kit-455-4210
Condition:
New
Please Call for Availability
Now ships in 15-17 Weeks!!! (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Option to send us your block
Choose Bore Size, Stroke, Crank, & Rod
Choose 4.250" Stroke
Create a...More Details »
Item #: BP-SB-Kit-455-4250
Condition:
New
Please Call for Availability
Now ships in 15-17 Weeks!!! (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block Kit
Option to send us your block
Choose Bore Size, Stroke, Crank, & Rod
Choose 4.500" Stroke
Create a...More Details »
Item #: BP-SB-Kit-455-4500
Condition:
New
Please Call for Availability
15-17 weeks (slightly longer for full custom pistons). Ships to business address. Residential or liftgate are available for additional charges
Description:
Customized Butler Performance Short Block
Choose Bore Size, Stroke, Crank, & Rod
Choose 4.250" or 4.500" Stroke
Create a custom package tailored to...More Details »
Item #: BP-SB-Kit-505-541
Condition:
New
Please Call for Availability
Contact us for lead time. Contact sales@butlerperformance.com for more detailed information. Ships to business address. Residential or liftgate are available for additional charges
Items 1-21 of 21
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More About Long Block Kits (Unassembled)
1. Where a long block kit sits in the lineup
Butler's kit names are literal, and knowing which one you are looking at saves a phone call.
| SBK — Short Block Kit | prepped block plus rotating assembly. Crank, rods, pistons, rings, cam bearings, main and rod bearings. No cam, no heads. |
| LBK — Long Block Kit | everything in the SBK plus cylinder heads. |
| KIT — full engine kit | the long block plus camshaft, lifters, timing set, gaskets, oil system and intake. |
| Unassembled | the parts are machined to fit each other but are not bolted together. You set the final clearances and torque the fasteners, and Butler will talk through the numbers with your machinist. |
2. Choosing the block and the stroke
The block you start with sets the stroke ceiling and the bore range, and those two set the displacement. The kits listed here cover the whole ladder.
| 350 block | 3.750", 4.000" and 4.250" strokes with 3.905" and 3.935" bores, on Ross custom pistons. |
| 389 block | 3.750" for 395-400 ci, 4.000" for 421-427 ci and 4.250" for 447-454 ci. |
| 400 block | the widest spread, from 3.750" at 406-412 ci up through 4.210", 4.250" and 4.375" to a 4.500" stroke at 487-495 ci. |
| 428 block | 4.210", 4.250" and 4.500" strokes on the 3.25" main journal casting. |
| 455 block | 4.210" for 462-469 ci, 4.250" for 467-474 ci and 4.500" for 494-501 ci, with pistons bored 4.181" to 4.211". |
| Aftermarket IAII block | 505 to 541 cubic inches, 3.00" mains, 4.250" or 4.500" stroke and Ross pistons to suit the bore you pick. |
3. Rod length, main caps and the budget block
These are the details that decide whether a combination works or fights you, and they come straight out of Butler's own build sheets.
| Rods follow the stroke | 6.625" I-beam rods on the 3.750" stroke, 6.700" H-beam on the 4.000" and 6.800" H-beam on the 4.250" and longer. |
| Long strokes want better caps | four-bolt billet main caps are recommended on the 4.500" stroke combinations. |
| Balance | these assemblies are balanced internally, which changes what flywheel or flexplate you need on the back of the engine. |
| 557 casting caution | the 557 model 400 block is the budget option and is offered at 3.750" and 4.000" stroke only, rated for under 500 horsepower. If the plan is more stroke or more power than that, start on a different casting. |
4. What you still have to buy
An LBK is not a runner. Plan on a camshaft and lifters, a timing set, a gasket set, an oil pan and pickup, an oil pump, an intake manifold, a damper and a flywheel or flexplate before it fires.
| Compression | give Butler your head casting or chamber cc with the order so piston selection and final compression are settled before machining, not after. |
| Valvetrain | pushrod length depends on your lifters and rockers, so measure on the actual parts rather than ordering to a catalog number. |
| Balance parts | internally balanced assemblies need a neutral balance damper and flywheel or flexplate. |
If you are torn between two strokes or two bores, call with the car, the transmission, the rear gear and how you actually drive it. Butler spec's these combinations every day and will steer you to the one that suits the car instead of the one that sounds biggest.
Not sure what your Pontiac needs?
Email our tech team at tech@butlerperformance.com. Tell us your engine, heads, car, and power goal, and we will put the parts together as one combination that works.