I think the car should be in the 13's as is. You may have a healthy enough of a 350 to graduate to a bigger carb. I'm running a 15.4 at 88mph in a truck with 29.6" tires, a 3.07 gear, a stock converter, a stock qjet carb, and stock hei ignition. If I went to a 3.73 or 4.11 gear, I could probably be deep in the 14's. My motor is a lot more conservative with only 212 degrees of duration at .050" and .447 lift overall for the cam and 9.25:1 compression. My best 60' was a 2.318. A performer RPM intake for you will probably match the cam a little better as well.