I have just pulled a set of 3.55 gears out and went back to 3.91s and I street the car all the time with a similar cam in a small block. Why is everyone afraid of a engine holding 3000-3500? Don't want the buzz use 29 to 30 tall tires. I was driving the car for 2 years with 4.30s and for 8 month's 4.56 gears that was too much in Qtr the 4.30s were fine. and the 3.91s gave me great qtr mph forwhat it is, keep in mind heavy cars do need the gear. My Duster has 4.10s for over 30 years. I would drive it hunderds of miles never a problem. The 3.55s were ok but did not have the top end pull