Well Paulie, always good to try something,and it’s your car and bank account. Just remember you are trying to make up 11.4% of torque multiplication from the gear change alone, 60 ft lbs or so, and even more when you take out converter, just to break even
With a cross bolted 427 based stroker with a ported TW, I would be letting it eat if you are running out of rpm with the current motor, that is if being real is street racing