almost everything i bought frome the spectre isle at auto zone has failed. the valve covers rubbed on one of my rockers and caused it to break i could actually see the side of the valve cover pulsating because the rocker arm was rubbing it that hard, the valve cover wing studs ya know the kind that have the wings that spline on, come loose very easly and the wings splines strip easly, breather barely fits with the rubber o rings they sell. i think its the distributor clamp that causes my distributor too leak. i just put a new gasket on it and tightend it down and it still leaks and it barely fits with the intake and looks like its pushing the distributor over instead of holding it down. the header bolts with the allen head tool didnt hold up and stripped the allen key out. vaccuum plugs dont hold up long,glass fuel filter sux, the stupid air cleaner screw exstensions that allow u to put bigger air cleaners on your carb loosin up and the little finger nuts that help tighten the extensions can loosen and fall into the motor through the carb. thermastat houseing sux, i think the only things i got from them that hasnt failed is the fuel pump backing plate, the bolt spreaders for the valve covers, heater hose fitting and pipe plugs.