Here is an NOS radiator top plate for 1970 Chevelle SS models with the large 4-core heavy duty cooling radiator, which includes factory AC big-block cars, those with 4:10 gears as well as those with heavy duty cooling option V01. I believe most LS6 cars would have this plate. These plates were notched at the driver's side corner with a larger tab spot-welded in at the factory to accommodate the larger radiator. This plate is in overall nice shape for an NOS piece with no rust.
You can see that the factory-dipped paint is still present, as well as the GM parts sticker and GM pick tag from when it was ordered over 25 years ago in 1994. There are a few scratches and nicks, and one small ding from the backside, so its not perfect. Note also that this a service replacement, so it has a threaded nut spot-welded to it that would not be on an assembly-line 1970 plate. This can be easily removed and welded over by someone with some good metal-working skills. Lastly, the welded-on tab has some impressions on it from the manufacturing process that were there prior to paint application.
These can be clearly seen in one of the close-up photos. Please be sure to view all photos closely so you can assess overall condition for yourself. The item "NOS 1970 Chevelle SS LS6 Radiator Top Plate Heavy Duty Cooling V01 4 Core 410 70" is in sale since Sunday, February 16, 2020. This item is in the category "eBay Motors\Parts & Accessories\Vintage Car & Truck Parts\Engines & Components\Complete Engines".The seller is "malibu_400" and is located in Ridgefield, Washington. This item can be shipped to United States.