* Engine Bay Size: The 350 is considerably larger and heavier than the 2.2L. You'll almost certainly need to significantly modify or fabricate engine mounts, potentially even modifying the firewall and inner fenders to accommodate it.
* Transmission: The 350 will require a different transmission. You'll need to find a transmission compatible with the 350 and figure out how to mate it to the S10's transfer case (if you have 4WD) and driveshafts. This often involves custom driveshafts.
* Exhaust System: The existing exhaust system will be completely incompatible. A custom exhaust system will be needed.
* Wiring Harness: The 350's engine wiring harness is completely different from the 2.2L's. You'll need to either adapt the existing harness (extremely challenging), use a custom harness, or use a standalone engine management system.
* Cooling System: The 350 generates significantly more heat. The existing radiator and cooling system will likely be inadequate, requiring upgrades.
* Brakes: The added weight and power of the 350 necessitate a more powerful braking system for safety.
* Suspension: The extra weight may require suspension upgrades to handle the increased load.
* Fuel System: The 350 will require a higher-capacity fuel pump and possibly larger fuel lines.
In short: This isn't a weekend project. It requires significant mechanical knowledge, fabrication skills, welding expertise, and access to specialized tools. Many people choose to enlist the help of a professional mechanic experienced with engine swaps for a project of this magnitude. The cost can be substantial, easily exceeding the value of the truck itself if you're paying someone else to do it.
