The gear change will for sure make a big difference, a proper converter will put it over the top. Do the gear change and drive it, you'll see for yourself. It will still lack a lot from a standstill. Once you get up into the powerband it will come alive. A converter swap will make it come alive from a standstill.
I swapped from 2:76's to 3:55's and it did indeed make a huge difference, I have yet to replace the converter, but I'm wanting to.
