Well, the engine is going to be an Offenhauser indy car 4 cylinder. Not much detail here, just some wiring and hoses, etc.
While this engine wouldn't be a "real" option, I'm using it as a "what if" type of build, after all it's just to be different. . .
Here's a pic of how the engine fits. . .
The radiator is from a 37 ford street rod.