CB,
IF you do have the 33-245-4 cam, it is not listed as .248 @ .050 as Steve denotes as beeing "too small". Its a 282S which is 236 @ .050, and a tad smaller even more. I ran this cam in my last car. Its a good cam with a wide power band, not overly radical.
I would guess your results do relate to your existing carb setup combined with mild porting (did that include a port matched intake job?), and the camshaft you are using.
Try changing to a properly jetted HP carb with a little more cfm. and I bet you'll pick up some more HP. Good luck.
Check Here - Is this your Camshaft?