Minecraft barrel model?

I made a barrel model file for a Minecraft Texture Pack. If I now place the barrel I can see through the blocks where the barrel is placed. I know that when I save the .json file as Anvil you can't see through the blocks. But then it would be ingame the Anvil with the model. Now my question is there any way to take the model for the barrel without looking through the blocks?

Can you possibly change the hitbox or something? I think the anvil is a little different and more appropriate.

I do not know my way around but can go if you edit the textures in your program by looking again that the size of your texture matches the size of the "sheet".