My research before I bought my diesel said 1985 was the magic year -- before that one had to replace all the fuel lines. Also, the old lines won't dissolve overnight, just over time, so it isn't required before you run bioD (any leaks that do happen suddenly were there already).
I bought a kit from
www.greaseworks.org for mine. Expensive, but everythihng is precut and all the clamps are include along with three pages of directions. If you need help knowing what to do, I recommend their kits, else get the parts and go for it.