The OBD factor is an issue for you in trying to get most engine sensor, mechanical, body electrical and transmission off of the 98' for use on the '94. Mostly anything that hooks up to a body control module or a PCM or just about any other electrical control of the power train will not be useful. The mechanical things like the intake manifold, exhaust manifold, some internal engine mechanical parts, brakes, and the like will be useable. However, anything that has to do with computer control will not be able to be used.
So mostly just the body panels, interior door cards, seats, and other associated non-computer connected pieces. I am sure there a few things electrical you could cross over with, but few will be usable.
The cross-over points for your ZJ will be from '91(if you could find one that early) - '95. Anything from 96-98 will have the issues I aforementioned.
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