Voltage Regulator
the VR in my 76 B200 lasted 10 years (at least). I sold it in 86 and purchased a new B150. The vr in it lasted for 301,000 miles until I sold it in 94. the fellow (a co-worker) who purchased that van drove it until about 3 years ago. When he sold the van with 460,000 miles on it, it was still going. Only changes to that van in the first 460,000 miles were the regular wear items, and a water pump about ever 65K miles. lol