Why A Small-Block 400 V8 Exists In This 1970 Chevrolet Impala  

The existence of a small-block 400 V8 engine in the 1970 Chevrolet Impala can be attributed to a combination of factors.  

Firstly, during this era, General Motors introduced the 400 cubic inch displacement engine as  

a means to comply with emission regulations while still delivering respectable performance.  

The small-block 400 V8 was designed to strike a balance between power and efficiency.  

Secondly, the Impala was a versatile and popular model that catered to a wide range of customers,  

including those seeking a balance of performance and fuel economy.  

By offering the small-block 400 V8 as an engine option, Chevrolet provided buyers with a more economical alternative to the larger,