I did find a previous post on this subject but couldn't make heads or tails of the guys "snake oil" response.

What exactly is the point of a TB spacer? All it really looks like to me is a small gimmick kinda like the air foil.

A 10HP gain would be nice, but for $100 this thing hardly seems worth it as I can't see it giving much over a couple HP...

 

Spacers on a carb like TB intake can help the air and fuel (on a TBI) make a better transition into the runners on higher powered engines and increase plenum volume by a high enough % to actually do a little bit of good. Spacers on a carb can do the same as well as isolate heat that would warm the fuel in the bowls. None of these really apply to a TPI.

The only time a spacer on a TPI t/b might help and is by giving the air a longer and little better chance of clearing the stock EGR wall in an untouched stock plenum. If you ported the plenum and knocked down that wall (free mod),,, then I can see very little to no benefit from it at all. Maybe,,, just maybe it might give a couple horses on the higher horsepowered TPIs giving the air a little more room to make the turn at the closest set of runners, but I wouldn't expect anything at all from the lowered powered TPIs,,, unless the spacer had nitrous spraybars in it.

 

Some of the spacers have a spiral effect on them which is to help mix air. This only works on carbs and TBI's. It does nothing for multiports.


The only thing I see it working on for TPI is a space to drill holes for nitrous.

 

It increases the plenum volume a little, which has some effect on the power curve, but as for it adding "power" I think you'd be better off spending your money somewhere else.