* Engine bay space: The S-10's engine bay is relatively small. Larger engines will require significant modifications, potentially including firewall modifications, custom mounts, and extensive fabrication.
* Transmission: The stock transmission will likely be insufficient for a very large engine, necessitating a stronger transmission and potentially a custom driveshaft.
* Axles and suspension: The stock axles and suspension components aren't designed for the stress of a significantly larger and more powerful engine. Upgrades will likely be necessary to handle the increased torque and power.
* Legal considerations: Depending on your location, regulations might limit engine swaps, and you might need to obtain inspections and permits.
While some enthusiasts have successfully installed large-block Chevy V8s (like a 454 or even bigger), it's a substantial undertaking that requires significant fabrication and modification skills, or a substantial investment in professional fabrication work. It's far easier and more cost-effective to fit a smaller big-block (like a 350) or a robust small-block V8.
In short, while technically you might *be able to* squeeze in something enormous with enough custom work, practically speaking, a moderately sized V8 (around 350 cubic inches) is the upper limit for a reasonably feasible swap. Anything larger becomes a massive project with considerable expense and complexity.
