* Backspacing: The crucial measurement is backspacing (the distance from the wheel mounting surface to the inside edge of the wheel). 1968 Coronets have a specific backspacing requirement for their wheel wells. An 18x9.5 wheel, especially with a common backspacing for that size, will almost certainly have too much offset (meaning the wheel sits too far out) This will cause clearance issues with the suspension, body, and potentially the fenders.
* Wheel Well Clearance: Even with correct backspacing, the wider 9.5-inch width might rub the inner fender wells or suspension components, especially during turns or with suspension articulation.
* Bolt Pattern: You also need to match the bolt pattern (number of lug nuts and their spacing). While you haven't specified, you'll need to ensure the bolt pattern of the 18x9.5 wheel matches the 1968 Coronet's.
* Tire Size: The tire size you plan to use on the 18x9.5 wheel will also heavily influence fitment. A large diameter and wide tire will exacerbate any clearance issues.
To determine if it will fit, you would need:
1. The specific backspacing of the 18x9.5 wheel.
2. The bolt pattern of the 18x9.5 wheel.
3. The intended tire size.
4. Research the stock wheel and tire specifications for a 1968 Dodge Coronet. This will give you a baseline for comparison.
Only with this information can you even begin to assess the feasibility of fitting the 18x9.5 wheel. You might need to consult with a wheel and tire specialist or a classic car restoration shop. They can help you find wheels that will fit properly without modifications or identify the necessary modifications if you're determined to use 18x9.5 wheels.
