Isn't the interior a 70s/60s Muscle car? Also, you got it correct, although this part is easy to identify the game. You just need to know where and only that car appears in Forza.
Sadly i'm not familiar with forza games Most I can do without googling is guess the car itself Hint: It's early-mid 1970s, but not a muscle car.
nope --- Post updated --- Same time period, and it's also japanese. The engine is only slightly bigger than the 100A's engine