Nice work BDJ. Narrowed throttle shafts are a great way to increase CFM. Sound like you have a lot of experiance. Things like this are basic, but very over looked. I would sugest from a business stand point to do a flow bench before and after your work. I would bet you pick up 20cfm. That throttle shaft is realllllly thick. Could the throttle body be bored out and a larger and thinner butterfly be installed?