I also have a 73 Mustang convertable with a 351 cleveland with a 4 speed that will pick up the wheels slightly if i get good traction. If i take off from a dead stop it wont, but if i going say 5 MPH and play with the gas alittle then make it hit hard it will lift. Mind you this is with 60 series radial tires not slicks.
In my drag Cougar i have a 514 BBF, and it will lift the wheels off the ground alittle when i launch the car. But i have it set so the wheels lift as little as possible.