A quick search of the internet and you can find many examples of the first generation Chevelle in wagon form, but not too many of the '68-'72 examples. Either GM didn't build many wagons in the second generation, they've all been crushed, or owners don't want to sell them. Either way, asking prices for the ones around seems to be reasonable.
This Chevelle is powered by a 307 cubic inch small block Chevy with a base 2-barrel carburetor that was rated at 130 SAE net horsepower when new. That may sound pretty abysmal, but it was really only a few ponies down from the '71 base 350 V8 rated at 245 SAE gross horsepower, which when comparing apples-to-apples was 165 SAE net horsepower.