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Grannys Tranny Sm465 Transmission Upgrade Sm420 Transmission And Spicer Transfer Case

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This is the old standby when it comes to Willys Jeep transmission and transfer case combos: the GM SM420 and the Spicer 18 transfer case. This allows easy adaptation to a GM engine like a V-6 or V-8 since the transmission came behind a GM engine. The SM420 has an immense low range of 7:1 and was last offered in a GM vehicle in 1967.

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