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Jeep 4 0 L Engine

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The 4.0L Jeep engines found in XJs, ZJs, YJs, and TJs are all good. But if you’re looking for an easy swap with great aftermarket support, the ’91-’95 engines have a user-friendly OBD1 computer that can withstand modifications without going all 2001 Space Odyssey on you. Look for block casting number 53008405 to identify the ’91-’95 and 53020569 for the ’96-’99. The later blocks will also have NVH after the casting number. As for the cylinder heads, the ’91-’95 7120 castings are almost as good as the ’96-’99 0630 castings, so don’t knock yourself out.