Any idea what low gear ratio is in the trans? If it's 2.54 like I suspect it is, I'd use mid to high 3's. It might be easier to look for a Sag with a higher low gear ratio and swap it in. It'll be much easier to get moving from a dead stop, and you won't have to slip the clutch so much. I went from 2.54 to 3.11 in a Nova with 3.08's and a 350, and it was like driving a whole 'nother car. Clutch life was more than doubled.