Hector
I hate to rain on your parade, but
if you still have the 2.45 or less rear gear in it, both the 4bbl and the cam were a total waste of time. The secondaries when properly adjusted will not come in before 3500 rpm, which with a 2.74 low-gear is 41 mph. 41 mph,41 mph. With a 2.45 low this is 45 mph. The bit of a cam,may have stolen some of the torque you had, off the line.
But if you do bring the secondaries in earlier,and assuming the engine does not immediately detonate itself to death, then the secondaries will add nothing to your engine at all, cuz the 2bbl was good to to perhaps 4000 rpm all by itself. All the 4 bbl will do is share the airflow between four venturies instead of two, and now the airspeed thru those venturies has fallen to 50%, making jetting nearly impossible.
Your engine might be able to pull 414 cfm@ 4500@58 mph with 2.45x2.45x 26 inch tires at 100% VE. More likely is perhaps 310cfm @75% VE.........Your 600 is crazy big. Twice as big as the engine can use.
Lets say you put 4.10s in there.This brings the mph down to 4500=35mph with a 2.45 low. But your carb will still pull no more air than before, or about 310cfm
If you want performance
You have to get rid of those 2.45s or less.
Please say the 2.45s are gone.