Best Place to Mount The ECU?

I'm putting a 65 cuda back together and converting to E.I so I need some advise on where to mount an ECU. The old engine hanness was toast so I bought a new harness set up E.I. from Herbs, and the length of wire connector to the ECU is limited to locating it to the firewall. Please see attached picture and tell me what you think the best location is? I'm putting a 340 with a stock distributor and I want to make sure everything clear before I put it in.

Thanks