How can I determine the engine size of my 68 Camaro

The engine size is not in the VIN on a 1968 model. If the emission control sticker under the hood is still there, that will tell you. If not, the information is embossed on the front left side, facing the engine from the front of the vehicle, of the block just below where the head and block meet. I'm assuming this is a V8 engine. Hope that helps! Jim