Thank you. The mat looks like a much newer product, I didn’t see any markings but I’ll go back and have a look.The trunk cleaned up nice. Excellent condition as it appears very original. The mat might be too. They were included with deluxe interiors, originally. The sticky substance is common from old rubber breaking down, I guess. Did you see any numbers? Here are some photos of factory mats....Trunk Mat original? | Team Camaro Tech (camaros.net)
I used a flat file to make sure it was flat. I think the problem is that I put the gasket on first and then the thermostat and it didn’t seat right, and when I pulled it off and stuck it back down it wasn’t good still. I ended up taking it all off, cleaning all the RTV off and used a Mr Gasket with a silicone ring. The last time I started it up it didn’t leak but I didn’t have it running for very long because I have a gas leak I’m still dealing with and waiting on parts for. That’s pretty much the final (known) hurdle before I can adjust the timing and actually get in it and drive somewhere. No leaks from the new manifold plug I installed, which I used RTV on.A couple notes on your engine leaks; Check the thermostat housing for flatness with a straight edge as they warp easily from over tightening, especially if using a thick gasket. They can be straightened with a large flat file fairly easy. Also check for cracks around the ears. Coat the surfaces sparingly with RTV.
I'd use teflon tape on the manifold plugs. Check the heater core nipples to make sure they're not deformed. A standard hose clamp like you're using should work fine. Do not overtighten.