Bill,
All 34-39,40 Lincoln K models were 414 cubic inch V12s. 150hp and 312ftlbs of torque. No Lincolns of that era were 404ci.
Chuck
The KA's 381.7 cubic inch V12 was enlarged for 1934 to replace the 1932-design 448. This new engine displaced 414 cu. in. (6.8 L) and produced 150 hp (112 kW). All Lincolns in 1934 (both KA and KB models) were powered by this new 414 V12, and the distinction between models was dropped, with all 1935 Lincolns being simply branded "Model K". The 414 would last through the end of the Model K's production just before World War II.