I have a 1999 sierra 5.3 and this vent valve fit on without any trouble at all. even the stock hose fit right up...only thing was because this valve is a bit bigger the bracket needed a slight tweek (just bend it a bit).
Don't think twice about using this part number...it's a no brainer fit.
Hey all. long time reader, first time posting and wanted to add another thumbs up for the A/C Delco part# in this thread.
My truck is a 99 Sierra Z71 5.3l and the newer valve, although bigger fit right in the original position with only a minor tweek of the bracket. Not only that, but even the hose fit on just like the stock one.
Props to everyone here ahead of time for all the monies your gonna save me.