Exceedingly bored right now, having withdrawls from not being able to work on my truck. Never thought this would happen! Probably not as bad as a drug addiction, but man! So I've just been searching forums, data, etc. as things pop into my head. Found this post about the swirl port TBI heads. http://thirdgen.org/techbb2/showthread.php?s=&threadid=268064&highlight=throttle+body+shaft Yes, geared more toward the cars, but as usual, look where the Vortecs are in that comparison, and think about what application the Vortecs were used in.