Will a 3.3L motor from 91 voyager work in 96 with 3.0 it?

No, a 3.3L engine from a 1991 Dodge Voyager will almost certainly not work directly in a 1996 Dodge Voyager with a 3.0L engine. While both are V6s, there are significant differences between the two engines and the supporting systems (wiring harnesses, engine management, etc.) that make a direct swap extremely difficult, if not impossible. You'd be facing a massive undertaking requiring significant fabrication and custom work.

Key differences likely include:

* Engine Mounts: The engine mounts are different and won't line up.

* Transmission: The transmissions may not be compatible. Even if they appear similar, the bellhousing bolt patterns are likely different.

* Wiring Harness: The engine control module (ECM) and wiring harness are completely different. Adapting this would be a monumental task.

* Exhaust System: Exhaust manifolds and piping will not match.

* Accessories: Power steering, alternator, and other accessories might have different mounting points.

In short, while the displacement difference doesn't seem huge, the underlying engine design and supporting systems are sufficiently different to make a direct swap impractical. It would be far easier and cheaper to rebuild or replace the existing 3.0L engine.