Short Blocks (Assembled)

Short Blocks (Assembled and Unassembled Kits) - Short Blocks (Assembled)

Pontiac V8 Short Blocks (Assembled)

Built and Sealed — Short Blocks (Assembled) for Pontiac V8s

An assembled short block is the same parts list as a Short Block Kit — prepped block, crank, rods, pistons, rings, cam bearings and main and rod bearings — already built by a Butler engine specialist. No camshaft and no cylinder heads. You take delivery of a sealed bottom end instead of a pile of boxes.

Butler assembles these on 389, 400, 428 and 455 Pontiac castings and the aftermarket IAII block, in strokes from 3.750" to 4.500". Assembled short blocks include a Viton rear main seal and ship on a reusable engine cradle.

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389 Block
Pontiac V8 389 Block Keep the 389, Lose the Guesswork — 389 Block for Pontiac V8s An assembled 389 short block is a finished bottom end: a machined 389 block with the crank, rods,...More Details »
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400 Block
Pontiac V8 400 Block Pick the Stroke First — 400 Block for Pontiac V8s The 400 is the Pontiac block most people are actually holding, and an assembled 400 short block turns it into...More Details »
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428 Block
Pontiac V8 428 Block The Big-Journal Block — 428 Block for Pontiac V8s The 428 is the big-journal factory Pontiac block: 3.25" mains and a larger standard bore than a 400, which is...More Details »
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455 Block
Pontiac V8 455 Block Start Big, Finish Bigger — 455 Block for Pontiac V8s The 455 starts with more cubic inches than any other factory Pontiac block, so an assembled 455 short...More Details »
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Aftermarket Block
Pontiac V8 Aftermarket Block No Core, No Surprises — Aftermarket Block for Pontiac V8s When the plan outgrows a factory casting, the aftermarket block is the answer. A new IA II...More Details »

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More About Short Blocks (Assembled)

1. Assembled versus builder kit

Same parts, different handoff. Which one suits you comes down to what you want to own and what you want done for you.

Assembled short blockbuilt by a Butler engine specialist with clearances set, rings fitted and the rear main seal installed. It arrives as one unit on a reusable cradle.
Short Block Kit (SBK)the identical parts shipped unassembled for you or your machine shop to finish. Right choice when your builder wants to set his own clearances.
Either waythere is no camshaft and there are no heads. That is what makes it a short block rather than a long block or a full KIT.

2. Choosing the casting under it

The subcategories are split by block because the block decides stroke, bore and the displacement you end up with.

389 block3.750", 4.000" and 4.250" strokes covering 395 up to 454 cubic inches.
400 blockthe deepest lineup, from 3.750" at 406-412 ci through 4.000", 4.210", 4.250", 4.350" and 4.500" at 487-495 ci.
428 and 455 blocksthe 3.25" main castings, run at 4.210", 4.250" and 4.500" stroke.
Aftermarket IAII block505 to 541 cubic inches when the factory castings are out of room.
Budget versionsButler's budget assembled short blocks use the 389 and the 400 557 casting and are rated for under 500 horsepower, at 3.750" and 4.000" stroke only.

3. What you add from here

A short block is a foundation, not an engine. You still need heads, a camshaft and lifters, a timing set, an intake, an oil pan and pump, gaskets and a damper before it runs.

Not sure what your Pontiac needs?

Call our tech team at 866-762-7527. Tell us your engine, heads, car, and power goal, and we will put the parts together as one combination that works.