The converter makes a difference for sure. Stock converter is </= 1400-1800. 4.3 Vortec converters are a little higher 1600-2000.I do understand the gear change will give me much better "off the line" pick up and that is in the plans however, What about blueprint calling for a converter in the 2,000 - 2,400 range? I gotta do one project at a time and right now it's engine swap. Gear swap can be a project coming up soon. I actually do mind the freeway gears.
No, a stock unit won't be optimum but one will do & is close enough to their 'recommendation' for now since it's a street car. Tell Blueprint you'll be running 2.28 gears & a 26" tall tire & I bet they'll be telling you to change things. I would opt for the v6/4.3 converter. Us poor boys commonly did that back in the day. Heck, I told my buddy (he works for GM) to search for a 'modern' version to go w/his 5.3/Stage2 truck cam LS swap into my old '90obs Chevy & to ask his guy that built the trans what he recommended. He said the 6cyl Vortec converter was still a good low budget choice.
Race car doing race car stuff? You definitely want to get the converter as close as possible to the engines needs. You'll also have the gearing already in place to work w/the combo.
*EDIT* OD/4spd trans changes the game & needs.