67/68 Lower radiator support mounts

[T0ple55]

What don't I know? This is a new core support and I am putting a new champion radiator in, Can someone help me understand what goes in these weld nuts? What's is there purpose besides not allowing my rubber grommets to seat down all the way. Appreciate the help, thanks

[Jason Banks]

Wow...I'm pretty sure those weld nuts should not be there. I just got done putting in an Auto Metal Direct 67/68 core support. That wasn't one of the problems I had. There was a spot weld in that exact location that I needed to drill out to fit my 4-core radiator lower mounts in. I would probably drill/chisel those out of there.

Make sure you test install that thing to find other problems. Mine had one of the weld nuts along the top in the wrong location...so my top radiator mounts would not line up. The tabs at the ends along the back edge at the top needed some massaging too. They needed bent down and one hole was way off.

[67c10rustbuket]

The nut is there for a bolt which installs from beneath. I believe the later trucks had the lower rad supports spot welded on but 67 they are bolted on. The rectangular tab goes onto the rectangle slot and bolt installs from underneath. The second pic has two locations for the lower rad support depending on which engine & radiator your truck came with. The rubber cushions have a recess in the bottom for this hardware.
Since yours are spotwelded on you don't need to bolt them on too unless you like redundant overkill. I do.

[T0ple55]

Thanks for the info guys!

[In The Ten Ring]

Just been working on my lower radiator support brackets, so this is one of the few things I can honestly talk about here.

On my 1972 the core support was factory and did not have lower radiator support brackets. All it had was a bit of rubber strip that the radiator sat on.

My replacement core support is from either a 1970 or 1971 (I forget) 396 truck from California. It had 4 row lower radiator support brackets that were riveted in. One bracket was installed incorrectly and the other was bent, making it a 3 row bracket.

I could not get my drill bit to center for drilling out the brackets but I was able to use my Dremel tool to grind off the bottom of the rivets and punch the brackets off the core support (core support was not on truck at the time).

With a bit more grinding and the use of my bench vice, hammer, and punch, I was able to remove the rivet from each bracket and restore the brackets. *I may or may not use them on my truck.

I then installed replacement brackets with a machine screw and nylon insert lock nut. This will allow me to replace those brackets with originals if I later see fit OR put in my old OEM (2 row) radiator if I decide.

The replacement rubber cushions I got from GMC Pauls's have generous space for the machine screw head, they may clear what you have. If not, you might could cut away more rubber to clear it or remove those and put in new or NOS/OEM brackets and machine screws like I have done.