The factory fuel rail in a Turbo III powered vehicle was poorly designed with a "rail within a rail". If you remove one of your injectors and look inside, you'll notice that design.   Our team modifies the factory fuel rail so that it now features a full 3/4" ID (rather than the tiny factory 5/16" ID) and will deliver much more fuel to your injectors!   This is a great performance upgrade for your Iroc R/T or Spirit R/T.   Please indicate if you are sending in your good core rail.  Note that we cannot accept rusted rails.  Your core must be in good condition in order to qualify for full core credit.