Well, according to this chart:
Air Pressure and Altitude above Sea Level
It says 7000 ft would be 586.7 mmHg while sea level is 760 mmHg.
So, 586.7/760 = 0.772 or about 77% of the sea level air, so I was a bit
on the low side with my 21% figure. It's actually 23% less air at 7000 ft.
6500 ft is closer to 21% less air (taking the average of the 6000 ft and the 7000 ft
pressure), so your 2.3L is actually a 1.82L.
