LS1 (Gen III small-block Chevrolet):
* Advantages: Generally more powerful, more readily available aftermarket parts, significantly lighter, better fuel economy (generally), higher revving potential. Easier to find performance parts and modifications.
* Disadvantages: Can be more complex and expensive to work on (depending on your skill level and access to tools).
LT1 (Gen II small-block Chevrolet, *not* the same as the modern LT1 found in the C7 Corvette and Camaro):
* Advantages: Simpler design, generally more robust (though less refined), often cheaper to maintain due to simpler design and readily available parts *though fewer performance parts compared to the LS1*.
Modern LT1 (Gen V small-block Chevrolet - found in C7 Corvette and Camaro):
This is a completely different engine than the Gen II LT1 and is a direct competitor to the LS engine family. The modern LT1 has direct injection and other modern features and is more comparable to the LS3 and LS7. It's generally more powerful and efficient than the LS1, but also much more technologically advanced.
In short:
* For sheer power and modern performance potential with readily available aftermarket support: The LS1 wins.
* For simplicity, lower cost of maintenance, and a more robust (if less refined) engine: The older LT1 is a better choice.
* Don't confuse the old LT1 with the modern LT1. The modern LT1 is a significantly different beast.
Consider what's important to *you*: horsepower, ease of maintenance, cost of parts, availability of upgrades. The "better" engine depends entirely on your needs and preferences.
