It would depend on the id of the TB. If they are 3" then one is enough for NA motor. One thing to keep in mind is the TB is passing only air unlike a carb where the throttle bore are passing wet flow... well the fuel displaces a given volume of air.
Missed one part of your first question... I have a GT40-88 garrett - so as much as I can get out of that turbo...
51 GMC 4.2 turbo Can't solved today's problems using the same technology/thinking that created them
