Question: what ls engine is the best?
Answer: LS9/LSA: Made for the 2009-2013 Corvette ZR1, the LS9 is a supercharged 6.2L engine rated at 638 horsepower — the most powerful of all small blocks. ... 
LS1: This is the one that started it all! ... 
LS7: Introduced in 2005, the LS7 sported 427 cubic inches, making it the largest small block ever.