Your words and our modest math skills lead us to believe that you bought the corn a week before you meant to grill it, and now you're asking for permission from us to add an extra week to the equation? We're not happy.
The first rule of corn-buying is, buy the freshest corn you can, as close to the day (or time) you will be eating it. Don't buy corn a week in advance. Half the sugar in traditional ears of corn turns to starch within three days of harvest - at which point you will find them not worth eating. Supersweet varieties of corn can be tasty a week or more after harvest, but still lose meaningful amounts of sugar.
For 80 ears, it seems possible to us you could have struck a deal with a farmer to have them cut the morning of the barbecue. Perhaps that is not an option where you live, but could you find out how often your supermarket receives shipments of corn at this time of year and plan to buy it on the day closest to your event? Um, next time?
That doesn't solve your problem right now, does it? We do offer a last-ditch suggestion for those times when you absolutely have to store your corn. You can also freeze them if you have room for 80 ears.
We also suggest cooking an ear or two the day before or the morning of your barbecue to find out whether the ears are still tasty and worth cooking. There's no point in feeding good people bad corn. They'll still love you, but they may not love your barbecues.