Starting a 671 Detroit after sitting for 35 years

We have a Ford N series semi with 671 Detroit that my grandpa parked after he ended his trucking business. I've heard countless trucking stories over the years, many involved Detroits. These motors intrigue me and I'd like to do some hands on learning. I'm not sure if it's worth the thought of starting it, but figured it'd be a good motor to learn on since it's no loss if I make a mistake. The truck does hold enough sentimental value that it might bring grandpa to tears if I saved it from be swallowed back in the woods. Grandpa said it ran fine when he parked it back in "about '79".



So can it been done?