I've searched the forums on "firewall", "adhesive" and read through all the related posts, but nowhere could I find mention of what product to use for the black adhesive/sealer that is applied around heater motor, hoses, plugs, etc to seal them. Application is 1970 Dearborn, built Oct. '69. I learned that this is supposed to go over the blackout, which is great, but what product is recommended? Please be as specific as possible, no generic "Oh, just use Body Shutz" comments, please.