Engine Rebuilder Kits

For the dedicated enthusiast or the professional machine shop undertaking a classic Pontiac V8 rebuild, the process of sourcing, checking, and matching dozens of individual components can be time-consuming, expensive, and riddled with potential compatibility issues. Butler Performance eliminates this hassle by offering comprehensive Pontiac Engine Rebuilder Kits. These are meticulously assembled packages that provide nearly every internal component needed to transform a raw Pontiac core (such as a 389, 400 or 455 block) into a modern, high-performance short block, all with components selected and sized to Butler's exacting standards.

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389 Block

Factory Bore 4.062" 3.75" Stroke 2.250" Rod Journal 3.00" Main Journal

400 Block

Factory Bore 4.120" 3.750" Stroke 2.250" Rod Journal 3.00" Main Journal

428 Block

Factory Bore 4.120" 4.000" Stroke 2.250" Rod Journal 3.25" Main Journal

455 Block

Factory Bore 4.151" 4.210" Stroke 2.250" Rod Journal 3.25" Main Journal

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Butler Performance

More About Engine Rebuilder Kits

The Core Advantage: Guaranteed Matching Components

The primary benefit of choosing a Butler Engine Rebuilder Kit is the peace of mind that comes from knowing every piece is correctly matched and sized for a high-performance application.

No Compatibility Errors: Every component, from the piston pin material to the main bearing size, is selected to work together flawlessly, eliminating common assembly headaches.
Performance Sizing: The kits are built using Butler’s performance blueprinting standards, meaning components like bearing sets are sized for larger bearing clearances ( $0.0025\text{in}$ to $0.003\text{in}$ is typical for rods/mains) required by modern, high-RPM Pontiac V8s.
Simplified Purchasing: Instead of dealing with multiple suppliers for gaskets, bearings, and pistons, the builder places one order for a high-quality, fully vetted component package.

Kit Tiers: Stock Replacement to Stroker Monster

Butler offers Engine Rebuilder Kits tailored to different power goals and displacement needs:

Kit Tier	Primary Goal	Key Components	Required Butler Service
Stock/Street Replacement	Reliable factory displacement ( $400\text{ci}$ or $455\text{ci}$ )	Hypereutectic pistons, stock-style rods, new cast crank (if needed), standard bearings.	Machine work (bore, hone, deck).
Performance Stroker Kit	Maximum displacement ( $461\text{ci}$ or $505\text{ci}$ )	Forged Steel Crankshaft, Forged H-Beam Rods, Custom Forged Pistons.	Machine work + External Balancing.
Max Effort / Race Kit	$700+\text{hp}$ targets	All forged components, upgraded piston pins, special bearings (e.g., Clevite H-Series).	Machine work + Internal Balancing.

What is Included in a Butler Rebuilder Kit?

A typical, high-performance Butler Stroker Rebuilder Kit includes everything needed to create a complete short block (minus the cam and oiling system):

Forged Crankshaft: Brand new, high-quality forged steel crankshaft (often $4.250\text{in}$ stroke for the $400\text{ci}$ block).
Forged Connecting Rods: Forged H-Beam or I-Beam rods with high-strength ARP rod bolts.
Custom Forged Pistons: Forged pistons (e.g., Ross Racing Pistons) sized to the desired overbore (e.g., $0.030\text{in}$ or $0.060\text{in}$ over) and compression ratio.
Rings and Bearings: High-quality piston rings (often moly or Total Seal gapless) and premium Clevite or King performance rod and main bearing sets.
Gasket Set: A complete gasket and seal set for the engine (minus the head gaskets, which are often purchased separately to match the specific aluminum heads chosen).

The Critical Balancing Requirement

The most crucial service offered alongside these kits is Balancing. Butler Performance offers two methods:

External Balancing: Required when using heavier original flywheels/flexplates.
Internal Balancing: The ideal choice for high-RPM engines. Butler balances the entire rotating assembly to a neutral (zero-balance) spec, minimizing vibration and maximizing longevity.

By choosing a Butler Engine Rebuilder Kit, builders receive a proven recipe for horsepower, coupled with the precision-matched components that save time and eliminate guesswork during the critical assembly process.