Looks good. I once had a '67 7500. Came with a Toro-Flow Diesel and they changed it to a 6V-53 Detroit before I bought it.
You have an interesting truck. Never seen a 7500 with Hydraulic Brakes before.
The 401 sounds great. I've had the smallest (305) and the largest (478), but never anything in-between. Also used to drive a 9500 with a 637 V-8 Gas.
Keep us posted on your progress.
