Hi, wondering if somebody could tell me what size the fuel pump outlet is on a 66 289 c code, want to fit some braided line and want to know the connector size.

 

It's not that simple. Braided like comes in various sizes with various connector ends. It depends on how you're trying to adapt it. It also depends on the pump you have. It might have a hose nipple, it might have pipe thread.

 

If it is a stock type pump then its 5/16 flare, but its been a long time since i did mine.