I recently had an exhaust manifold crack on my 94 silverado. It is a 2wd 350tbi auto. Upon removing the cracked manifold I realized that the flanges on the y pipe were worn too thin to reuse. While trying to decide which aftermarket headers and Y pipe to purchase to replace the old pieces, I started looking at some stock manifolds and Y pipe I had laying around from a 93 Z28. I bolted them on the truck just for the heck of it and much to my surprise they fit perfect. The Y pipe could not fit better...it looks like it is made for the truck. These manifolds are much more free flowing than the stockers and the Y pipe has bigger diameter tubing and more equal length tubes before the Y. My truck does not have a smog pump so I blocked off the ports on the manifolds. The only other things I had to do was reroute the plug wires and lengthen the o2 sensor wires. Not that this setup will flow as good as a quality set of headers and an aftermarket performance Y pipe, but it is definately a cheap alternative that is worlds better than the stock setup that I thought I would share. Has anyone done this before?