- Home »
- Catalog »
- Crate Engines and Builder Kits »
- Short Blocks (Assembled and Unassembled Kits)
Short Blocks (Assembled and Unassembled Kits)
Pontiac V8 Short Blocks (Assembled and Unassembled Kits)
Block Plus Rotating Assembly — Short Blocks (Assembled and Unassembled Kits) for Pontiac V8s
A short block, or SBK in Butler's shorthand, is the block plus the rotating assembly: crank, rods, pistons, rings and bearings, with no cam and no cylinder heads. It is the part of a Pontiac build where machine work and balancing decide whether the engine lives, and the part most worth handing to a shop that does nothing else.
Butler covers it three ways: assembled short blocks ready to drop a cam and heads on, builder kits with a Butler supplied block, and builder kits using your own core. All of them run the Butler Process on the block and an internally balanced rotating assembly.
Select a Sub-Category
Popular Brands:
More About Short Blocks (Assembled and Unassembled Kits)
1. Three Ways to Buy the Same Bottom End
The difference is not the parts, it is who does the assembly and where the block comes from.
| Short Blocks (Assembled) | built and balanced by a Butler engine specialist and shipped on a reusable engine cradle. You supply the cam, heads and induction. |
| Short Block Builder Kits with a Butler supplied block | the same machined block and matched rotating assembly, shipped unassembled for you or your shop to put together. |
| Short Block Builder Kits with a customer supplied block | you send in your own core, Butler machines it and matches a rotating assembly to it, and it comes back ready to assemble. |
2. Which Block, and How Far It Goes
Butler builds short blocks on the whole range of Pontiac V8 blocks, and each one has its own useful stroke window.
| 350 and 389 | the small-main blocks, built in 3.750" through 4.250" stroke. The 389 runs from roughly 395-400 cu. in. at stock stroke up to 447-454 at 4.250". |
| 400 | the most common core, offered from 3.750" to 4.500" stroke, 406-412 up to 487-495 cu. in., with dedicated budget builds for the later 557 casting. |
| 428 and 455 | the 3.25" main blocks, built 4.210" to 4.500", topping out at 487-495 and 494-501 cu. in. |
| IA II aftermarket | a new block for 505-541 cu. in., 4.250" or 4.500" stroke, when the factory castings run out of room. |
3. What the Butler Process Covers
Every short block on this page, assembled or kit, gets the same block work before a piston goes near it.
| Inspection | cleaned, magnafluxed and sonic tested, so a bad core is caught early. |
| Machining | completely deburred, bored and honed with a torque plate, line honed with ARP main studs, deck squared. |
| Assembly prep | cam bearings and brass freeze plugs installed, and the rotating assembly internally balanced, which means planning for a neutral-balance flexplate or flywheel. |
Pick the block first, the stroke second and the heads third, then call Butler with all three. The piston and the compression fall out of that conversation, and everything else on the build sheet follows.
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.