There are 4 quarts in a gallon, so 8.5 gallons x 4 (quarts/gallon) = 34 quarts. (Take note how the terms "gallons" cancel each other out, one numerator and one denominator, which leaves you with just quarts. This is a useful to know when doing conversions)
I did my oil change yesterday and did one gallon which equals = 5 quarts. And my dip stick claims it was Max. And one time i took it to a oil change place and they used 5 quarts. So 5 quarts would be my best bet. Most cars take 5-6.