Do I need a new converter?

If the heads have been ported by a reputable person, that makes the numbers ever more hard to understand.
But, the convertor is a good start.
Regards the cam, for a Mopar small block stroker With even modest track results desired, not what i would want.
Not sure how much you street drive, but that hydraulic cam is a pooch. Real similar To the cam i got rid of in my 360.
I had 260/266 600 lift solid in a 416 eddie motor very similar to yours that i drove everywhere, including 70 mile roundtrips to the track. With good heads and convertor that cam will cost that motor lots of power