Without knowing the specs of the motor, it's harder to know what cam to choose. Knowing the compression (what pistons & head info), intake/fueling set-up, & what your intended use of the vehicle is normally all has an impact of what cam could be better or worse. Cam manufacturers want to know as much as possible about a combo before making effective & educated suggestions.@ scoti what I'd I want to upgrade the cam
The current cam you mentioned is a popular grind. It works fine & sounds good.... that covers the needs of many. But, that same cam in two differently spec'd 350's can or will yield 2 different results.
Lots of stock 'rebuilds' simply use over-sized stock pistons to accommodate boring the cylinder larger to remove the wear. A bigger cylinder w/the same low compression dished-piston & replacement 76cc smog era heads will lack compression. If it has flat-top pistons & some standard GM smog era heads, there's @ least a little more compression to help create some power. Or, if it has those replacement dished pistons but some better flowing aftermarket heads w/smaller chambers, it could end up @ the same compression but the heads better flow numbers increase the power more than just the compression boost alone.
It's a balancing act. There are other factors as well to consider. It's a street car so pump gas right? If so, the cheap/low grade or the highest octane available @ the pump? The higher the compression the more complicated things get to make sure it works as expected.
I'd work on the gearing first & then the converter if it seems to run decent in it's current configuration.
What gear ratio? That depends on tire size, how many street miles vs highway miles it sees, & if track time matters.