Well your heads are the factory E7 heads which have a 65% exhuast output still making a single profile cam the optimum choice. With the 3.73 gears I recommend the B303 cam with .480/.480 profile to maintain driveability. If your trying to make the cam as big as possible becasue of sound and dont care about driveability the largest I would go is the E303 .498/.498 profile.
Remember though big lift doesnt mean big power you are limited by your E7 heads. If you are going to buy aftermarket heads in the future I would recommend doing that first before choosing cam.
If it was my car and I knew I was never going to use boost I would use this cam which is like a B303 with .480 lift but has a little different exhuast durration to help the smallish E7 heads make maximum power.
Steeda #18 Camshaft - Steet/Strip for 1985-1995 Ford Mustang 063-0018