416ci LT1-LT4 Long Block Engine - The LT1/LT4 416ci competition long block uses a new GM LT1/LT4 block with 4.070″ bore to produce the 416CI. This short block provides a strong foundation for NA engines making up to 750hp and can be customized to meet your needs. Categories: LT1-LT4 Engines, LT1-LT4 Long Blocks