This 434-inch stroker small-block Chevy was built to race and made 681 hp on the Westech dyno! But performance is more than just peak numbers.

Westech Performance tests a carbureted 427ci big-block Chevy street engine with 11:1 compression that made 622 hp on pump gas.

Sounds like Corvette engineers took a page out of Porsche's playbook and underrated the ZR1's power output.