360 intake on a 340? and casting number

So i've been trying to find my casting number with no real luck. When i searched, i found several threads that said the casting number was on the driver side under the head, but i'm having no luck finding it.

The other thing is that i ran the numbers on the manifold. 4095080. Which came up as a 360 intake.

Are there any good tricks for finding that casting number while the engine is in the car?(73' duster)