advise people all the time to do their homework when buying parts or when they’re modifying their car.  Both reasons are valid. 1. you want to make sure the parts you’re buying are GOOD QUALITY parts and 2. you want to make sure the parts you’re buying are the RIGHT parts. I’ve been a victim of both of those. And I’m sure you could add several more statements to this.  

Recently I found a set of polished valve covers.  I want this item on my car as it was standard on the 90-91 SC Saleen cars and they match the polished Vortech.  It was simple.  I was going to pay someone reputable to polish mine OR find a good set already done.  I found a set that was near another fellow Saleen owner.  I contacted the seller, who wasn’t willing to ship but they provided some decent pics and struck a deal.  My buddy went over to get them and really didn’t notice any issues.  He took them and had them wrapped up to ship for me and when they arrived there was a bunch of excitement… until I unwrapped them.  They look good at first glance. 

Once I looked them over and got in the right light you can see a couple of spots.  I flipped over the valve covers and noticed they had been welded in a couple of spots.

  
You have to realize that these castings are very porous. Add in the metallurgy technology 25 years ago and there will be voids in the castings.  This is challenging when you polish aluminum like this because you’ll end up with small voids and sometimes larger voids in the finish that end up looking like black dots or worse.  It seems these had a couple of spots that needed to be touched up and you really have to know what you’re doing when you weld cast aluminum or you’ll just end up making it worse.  These were done ok, but potentially could have been done better.  
The other possibility is that these were corroded in these two spots from coolant leaks, gas leaks, or oil leaks.  I’m going to guess this is the possible issue with these because the repairs are near places where things like that could happen.  

They are decent but I’m a picky buyer.  What may please others sometimes bothers me because of a small detail that was not right but “acceptable” by another person. So now I’m either going to have these touched up OR I just bite the bullet and have the ones I have done and run a risk of the castings being an issue when mine are polished.  I’ll probably have these worked over again.  Not really worth the risk on the others.  As the title states caveat-emtpor. Buyer beware.