Still not possible. A stock 289 has a 2.87" stroke and a 4" bore. If you bored the cylinders enough to displace even 325 cubic inches, it would require a 4.25" bore size. The absolute max you can go with oem 289/302 blocks is 4.060, and that's pushing it, the typical safe overbore is 4.040. Boring it to 4.250 would be through the cylinder walls and into the water jackets. And that's just to bring it to 325 cubic inches. lol And the article mentioned it was "bored out to 425 cubes" which would be a 4.86" bore. LOL The writer has no clue what they're talking about. You CAN build a 311 cubic incher from a 289 block, using an oem 302 rotating assembly, and a 4.060 overbore. Technically, you could cut down a 351W crank's main bearing diameter to fit into a 289 block, yielding a 3.5" stroke,(allowing up to 363 cubes with a 4.060" overbore) the only problem with that option is the 351W wasn't available until 1969, 5 years after the Munster Koach was built.
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