My question is can I put an 8 speed wheel in a 85 trek 660 I have a 2009 brifter set Id like to try on it.

Your Trek is probably spaced 126 mm OLD for a 7-speed freewheel/cassette hub. You can install an 8/9/10-speed hub (130 mm OLD) with a small struggle as it will be a snug fit. It won't do any harm but will be a bit of a nuisance every time you change the wheel.

I had a 1983 6/7-speed Trek 400 spaced 126 mm that I upgraded to a 130 mm 8-speed rear wheel and used it in unaltered form for a while and then "cold set" it to 130 mm just for the conveneince.

exellent thanks

That struggle will be repeated every time you need to put the wheel back in.
With every puncture repair. 130-126 =4..

your right there I havent tried the back wheel yet. I want to put vintage campy on it down the road so to speak. Which will take a few mths. I am curious as to how the bike will perform with up dated parts wheels and derailers shifters. thanks

Enjoy the experiment and it will be interesting to see if you want to go back to the old-school components after you've tried newer ones. How does that old song go.."How you gonna keep 'em down on the farm, after they've seen Paree..." Anyway, you won't hurt your frame going back and forth between 126 and 130 mm hubs.