What do you think Godzilla's insides look like?

Heck i dunno

Probably like most terrestrial mammals. Squishy organs and meat stuffs, that kinda thing :p

I LOVE GODZILLA: Boy what you be smoking?

^Now that's pretty funny and clever!!

I think it would be a gate to hell with a hundred atomic bombs going off XD

If you mean in general, then this: Maybe similar anatomy to a carnivorous dinosaur, with some sort of organ for producing his atomic breath.

Otherwise, be more specific on the version and type of version.

Take note and remember this: Godzilla has many different incarnations, all with different origins.

Titan of water some strong stuff