"I'm going to flush the radiator and block out tonight, any other ideas on what would cause it to over heat would be great"
Welcome to the Ford Barn!
TW & RK gave you excellent advice on cleaning your cooling system and I too endorse Rust911 over vinegar for rust removal.
As a precaution, remove any lingering grease/oil with dish soap as it will reduce chelant effectiveness. Back flush to get the most sediment possible out of the system.
Add Rust911, filling to just above the radiator flues. Start the engine and allow it to warm up. The Rust911 works better/faster if heated to 150°.
Let it sit for several days starting the engine periodically to heat/circulate the cleaner.
Once you're satisfied you've killed all of the rust in your system, drain and back flush with regular water. As a bonus, save the Rust911 and use it for soaking other rusty metal. The solution will be totally black when used up.
Refill to just above the flues with 50:50 mix of distilled water and your favorite antifreeze.
Most Model A overheating problems are caused by a crudded up radiator. If you later determine the radiator needs to be rodded out, cleaning the system is a great first step.