Found this. isn't a 383 a B so it would be on the rail infront if the intake
"Locate the engine ID boss. If the ID boss is located on the block's right side just below the cylinder head next to the distributor base, then the engine has an RB (Golden Lion) block; if the ID boss is located on top of the block directly in front of the intake manifold valley, then the engine is a B block"
