Are TBI spacers worth the money? What are the pros and cons of them? Also do they give more HP or are they just strictly for fuel mileage. Found some at a good price and thinking about getting them for my 350, Thanks!

 

^^^^^^^^This!!!^^^^^^^^^^

 

For your 91, it can help since the injectors are near the spacer. Newer engines No.

 

I've also wondred about this. I get really crappy gas milage, even with the new crate motor. the truck is a 91, but the new motor is 93. So far the only thing I have done to actually improve mpg is run 70 psi in the tires.
These spacers seem too good to be true . . . . and you know what they say about that.