Jerry - I just did some web searching for sources starting with your link to get "Permatex Super 300". All the listings, including the Advance Auto Parts link, I found showed "out-of-stock' or "not available".
A check of the Permatex main page for the original Part Number 80057 takes me to what is evidently the replacement for the "Super 300", now listed as
Permatex® Aviation Form-A-Gasket® No. 3 Sealant Liquid, 4 OZ with the new part number "80019".
My local NAPA lists the "80019" as
Permatex Gasket Sealer Form A Gasket Seal and is in stock, ready for pickup.
In case it helps folks "North of the border" in Canada, the Permatex Part No. is "CAN Item # : 58931".
Hope this info helps you and anyone else looking to acquire the product as it looks like the old "Super 300" isn't available any longer.
