My dad and I took a trip to Kansas last fall he drove his GS, I drove my Skylark. We both filled our tanks before we left, and I ran out long before he did. My car is set up like this-Low comp. 73 455 (w/Q-jet) 100% stock except for a mild cam, 2700 max stall converter, 3.73 gears w/ a 27" tire. His GS is set up like this-Hi comp. 70 455 (w/Q-jet) 100% stock, stock converter, 3.55 gears and a 27" tire. I followed him the whole way so we were both doing the same speed all the way there. The mileage on my car during the trip was 10 mpg, and his car was getting 16 mpg. The problem is not just on the highway, it also runs rich around town. Any help is appreciated, Dad is outta town this week and I won't be able to get in touch with him for a while. Thanks, Kevin
I'd say this is because you have lower compression, and a hi stall converter. Have you checked your vacuum advance? What timing are you running? How do you know it's running rich? What do your plugs look like?
