Really other then some sensors, it is a stright swap. The 2.8, 3.1, &
3.4 are all in the same engine family.
The 89 2.8 and 90 3.1 look the same execpt for the upper intake manifold
which is cast with 3.1 instead of 2.8.
You friend just needs to change the sensors over from the 3.1 to the
2.8, and use the mounts off of the 3.1. No need for any wiring work at all.
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