* Mounting points: The engine mounts, bellhousing pattern, and overall engine bay dimensions are almost certainly incompatible. The Sunbird's engine is much smaller and lighter, designed for a smaller, lighter car.
* Transmission compatibility: The transmission used in the Sunbird will likely not bolt up to the Caravan's transmission. Even if they shared a transmission type (e.g., both automatic), the bellhousing bolt patterns would almost certainly be different.
* Wiring harness and computer: The wiring harness and engine control module (ECM) are completely different and incompatible. Adapting them would be a massive undertaking.
* Peripheral components: The power steering, alternator, and other accessories are likely in different locations and have different mounting points.
Even if you managed to overcome the physical mounting challenges (which would be extensive custom fabrication), the differences in the engine management systems would prevent the engine from running properly, if at all. The cost of such a project would far outweigh the cost of finding a used or rebuilt 3.3L engine or even a more modern replacement.
