The 120 million Japanese yen in 1964 equaled about $331,500 at the time - an amount that equates to nearly $3M in 2021. Or to figure it another way, 120 million yen in 1964 equates to about 543,600,000 yen in 2021 - an amount that exchanges to nearly $4.8M in 2021.
The car Togawa is given to drive is a 1963 MG B.
This film is included in "Eclipse Series 17: Nikkatsu Noir", released by Criterion.
Interestingly enough the plot element of diverting the armored car off the main road onto a side road and then closing off the side road to other traffic was also used in The Killers (1964). Since these two movies were released around the same time it is unlikely that this plot line was copied but rather is a coincidence.