with the block in place, the throttle body's not fully open. You can see it for yourself with the hoses off. Looking at the 4th picture in the original post, when the gap is fully gone, the shutters are fully horizontal...anything less will give you less flow. I know this cuz i actually looked into my trottle bodies while cleaning them. The '90 model actually comes with a bolt instead of the solid limiting block...it's just there with nothing on the backside...so i took it out...it can't hurt to have better flow into the engine i figured.
