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- 428 Block
428 Block
Pontiac V8 428 Block
The Big-Journal Block — 428 Block for Pontiac V8s
The 428 is the big-journal block from the tail end of the muscle car years — a 3.25" main casting like the 455, but harder to come by and prized in the cars that carried it. Butler builds it as a stroker base without turning it into something else.
These Short Block Kits (SBK) use a Butler supplied 428 block with Ross Racing pistons, Total Seal file fit rings and performance rod and main bearings. Three stroke lengths are offered, and rod choice includes press fit I-beam or bushed H-beam. No camshaft, no heads, shipped ready to assemble.
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More About 428 Block
1. What the 428 gives you
The 428 shares its main journal size with the 455, which is the practical difference between it and the 400 family.
| 3.25" main journal | the 428 uses the larger main size, so crank, bearing and rear main seal part numbers follow the 421 and 455 side of the catalog, not the 350, 389 and 400 side. |
| Bore range | pistons are built across the 4.155" to 4.181" range, so the final displacement follows how the cylinders clean up. |
| Core value | 428 blocks are worth prepping properly. Every one gets sonic tested before it is committed to a build. |
2. Stroke and rod combinations
Three kits, and the rod spec is the thing that changes most between them.
| 4.210" stroke | cast or forged crank with 6.625" I-beam rods, supplied press fit and not assembled. Optional bushed H-beam rods are available. |
| 4.250" stroke | cast or forged crank with 6.800" I-beam rods, press fit and not assembled, again with optional bushed H-beam. The middle of the three and a strong street combination. |
| 4.500" stroke | cast or forged crank with H-beam rods. Four-bolt billet main caps are recommended at this stroke — the extra stroke puts load into the main webs that the stock cap does not need to see. |
3. Block prep, finish options and what comes after
Each 428 block is cleaned, magnafluxed, sonic tested, completely deburred, bored and honed with a torque plate, line honed with ARP main studs and square decked, with cam bearings and brass freeze plugs installed.
| Paint is optional | if you do not choose a paint option the block is oiled down before it is bagged, which matters if the kit is going to sit for a while before assembly. |
| Ross pistons, flat top standard | dish or dome is available at additional charge when compression needs moving. |
| Internally balanced | the damper and the flywheel or flexplate must be neutral balance parts. |
| Still to buy | heads, camshaft and lifters, timing set, intake, oil pan and pump, gaskets and damper. |
Supply your head casting or chamber cc when you order. On a 428 that is the difference between a pump gas engine and one that pings on everything you can buy at the pump.
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.