According to the ancient "How To Hot Rod Small Block Mopars" recipe for a 13 second 360, you'll need a cam with somewhere between 280-295 degrees of total duration, around .480-.510" of valve lift and an overlap between 60-80 degrees. These specs are for a hydraulic cam.
Seems like your Crane Fireball cam is right on the low end of these specs with .484" of lift. Makes sense, you're in the low 14s.
That book was written in the late '70s-early '80s by old Larry Shepard. Good info, just dated.
How about this Lunati cam? Little low on the duration based on the specs above but more valve lift and the power band is good for a street car.
Hot Street cam, likes 2800 converter, Hi-Rise type dual plane intake with 750cfm carb, headers, 10:1 compression and 3.73 gears. Likes up to 200HP nitrous.
- Advertised Duration (Int/Exh): 276/284
- Duration @ .050 (Int/Exh): 234/242
- Gross Valve Lift (Int/Exh): .513/.533
- LSA/ICL: 110/106
- Valve Lash (Int/Exh): Hyd/Hyd
- RPM Range: 2200-6400
- Includes: Cam Only
Part Number: 60404
or...
Comp XE284H might work too.
You get the idea.