head hunter
If you are going for mild street performance, the 302s are great. If you think you will want more street/strip performance, forget the 302s because they just dont flow well enough to make big power.
The 318 I had years ago ran a little over a half second faster with my ported J heads, compared to my ported 302s
but the 302s were much more driver friendly due to the better low end torque.
If it were me, I would save the money that was earmarked for the port job (maybe for some nice heads).