I think a 30% difference would be noticeable. 8)
Off hand, no. A stock converter will be better in your application.
A good cam for this axle and the rest of the setup is going to have 195-214ยบ duration at .050". The power band should reun in the 1500 - 4000 rpm range, with torque from 1500 - 3500. Your converter isn't ideal for this kind of thing.
IMO, and from other posts, it is easy to over cam and over carb the LA. Smaller numbers on these might not be good for bench racing, but will give you better throttle response on the street. (It's cheaper, too.)