Will a 360 fit easily into an engine compartment that used to have 318 for 1973 Dodge Dart?

No, a 360 is significantly larger than a 318, and while it *might* physically fit into a 1973 Dodge Dart engine bay, it won't be easy and will likely require modifications. The 360 is wider and taller. You'll almost certainly need to:

* Check for clearance issues: The 360's larger dimensions might interfere with the firewall, inner fenders, steering components, and other parts of the engine bay.

* Address exhaust system compatibility: The exhaust manifolds or headers will likely need to be modified or replaced to fit.

* Consider power steering and alternator placement: These components might need adjustments or relocation due to space constraints.

* Possibly modify or replace the motor mounts: The 360's mounting points may not perfectly align with those of the 318.

In short, while it's *possible* with fabrication and modification, it's not a simple "bolt-in" swap. It's a project that requires significant mechanical skill and potentially custom parts. You should carefully measure and compare the dimensions of both engines and the available space in the engine bay before attempting this swap.