I'm looking for alumium or stainless cover to replace the plastic one.

 

You're going to have to either make one or have one made. I've never even seen anyone post regarding a metal radiator fan shroud.

 

 

I'm not sure if you are looking for the top piece or the actual fan shroud, but I found these on Ebay. I bought the dual 12" for mine and it is well built
http://www.ebay.com/itm/NEW-ALUMINUM-RADIATOR-FAN-SHROUD-CHEVY-CAMARO-1982-1992-FIREBIRD-USES-12-FANS-/281135905021?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3ACamaro&hash=item41750178fdhttp://www.ebay.com/itm/NEW-ALUMINUM-RADIATOR-FAN-SHROUD-CHEVY-CAMARO-1982-1992-FIREBIRD-USES-12-FANS-/281135905021?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3ACamaro&hash=item41750178fd

 

Or you can buy a baking pan for $20 and cut your own holes for a lot less.

 

[URL="http://www.camarocentral.com/1982_1992_Custom_Fit_Aluminum_Fan_Shroud_w_Fans_p/rad-309c.htm"]

 

Or just look for an LT1 fan setup. I built this one for a guy in Israel. The radiator is technically for a 2nd gen but its dimensions are the same as a 3rd gen. I personally hate the cheesy look of aluminum heat sinks....err, I mean universal fan shrouds. I like the look of a stock appearance but to each their own.