I belive Ford's original paint was p/n 1713, Chassis Black. The best matches to this for the engine compartment are:
1. PPG DDL 9423
2. PPG's DAR 9295 has been suggested as well
3. Spray bomb alternatives - Dupli-Color's DE1635 , Rust-Oleum's Satin Black (#7777), and the most popular - Krylon's Semi-Flat Black (#1613).
4. Eastwood's underhood black
There was another which needed a percentage of flattening agent - but it escapes me at this moment