First, it depends on engine size - a bigger engine will get the same operating range on a bigger cam as a smaller engine will on a smaller cam. For around 300 cubes - you want a cam with about 200 to 210 intake duration at 050 lift max. That will give you a torque peak of around 3000 to 4000. The more lift, within reason, the better. For a moderate modified engine, somewhere around .400 to .500 lift. Hydraulic roller cams give more torque for the same duration because their opening and closing ramps can be steeper, but for a non-roller block, you have to use Crane's retrofit hydraulic rollers at about $400. Probably not worth it for a moderate engine. by all means check the cam mfg websites, they give operating ranges etc.
www.compcams.com, www.holley.com for Lunati,
www.iskycams.com, www.cranecams.com to mention a few. You want a fairly tight lobe center angle, like 110 or 108 which will give you more low and mid-range. A single pattrn cam (same duration both intake and exhaust) is also better for low and mid-range torque. One good example is Comp Cams Hi Energy 268. You can also check out some stock Ford hydraulic non-roller cams at quite reasonable prices at
www.oemfordparts.com For good torque, use a 4bbl dual plane intake like a Performer, and a small 4bbl vac secondary like 500 to 600 for a 300 size motor. If you want to use headers, tri-Y's are best torque headers, or a small tube 4 tube with long primaries and long collectors, even with full exhaust.