I've been looking at trucks for a few months now and have some questions about engines. I've owned a four 70's fords, these had either the 302, 351M or 400 engine.

I'm going to be buying a crew cab with a auto to pull a small 3500# camper and need something reliable for long trips. Some of the trucks I'm looking at have either a 390 or 400 engine.

I know nothing about the FE enignes. Could someone tell me a little more of the pros & cons between the 390 & 400 engine?