In 1970, big block engines increased from 427 to 454 cubic inches and the powerful 370 HP LT1 small block engine made its debut.
1970 sales were their lowest since 1962 (only 17,316 units) due to a late start in the production year.
The first ZR1 performance package appeared in 1970
(not 1990, as some might believe) and included the 370 HP LT1 engine and
a host of other performance items.