Has anyone ever replaced the idler pulley with an aftermarket one on a vin w motor. The stock idler has a steel cup that sits on the front of the idler and rides on the inner bearing. Not sure what purpose it served but it doesn't interchange with the aftermarket pulley so I didn't use it. Got the idler at carquest and it looks just like your standard pulley but its made out of steel unlike the stock one which seems to be made out of plastic. Just wondering if anyone has any input, thanks.

 

I wouldn't worry too much as it is only an idler pulley. The most important part of it is the bearing.

And I did change one out on a 350 that was pretty much the way described the differences between stock and aftermarket and no problems at all.