when I bought my 84 1008, the reciept for alt belts from napa was still in a bag on the floor board of the truck. The reciept date was about 30 days prior... (old belts in bag) I dont know if they were economy or napa gold but they are already ready for replacement, thier stretched* (about 60 days old now).
The belts are at end of adjustment, set by me when I did both alts the first week or so I owned it. I think maybe shorter belts are in order when replacement is absolutely necasary*. I have also had issues with this on the power steering belt on my 79 chev......sometimes replacements are too long/different manufactures and things.....maybe someone could measure the belts for length and post that when they do replacement if correct, i'll take a tape measure with me when I buy mine and there wont be any surprises!