Harry, here's my lower radiator view. You can see that the crank snout just peeks into the rectangular slot shown above. Not much contact.
Also seen here is a very helpful and strong new attachment for the radiator. I enlarged the screw holes in the grille shell to .080. Then made 'studs' out of 2mm threaded rod and nuts. Nut at the top, a drop of CA and into the holes. Then a drop of epoxy to secure them in the shell. Carve a little clearance for the nuts in the plastic bottom corners of the rad. The studs come through the crossmember and the constant removal and replacement is a plug in - no more wiggly, stripped skinny Pocher screws. You can see here the nut and washer from the bottom which snugs it up. Very sturdy. Getting the firewall and grille shell sturdy is very important. When you make the brace rod between them, it hold the positions of these vital parts solid for body and hood attachment.
If you didn't drill the firewall for the Koo-recommended 8mm down from top rod location already, I can show you an accurate attachment using a clevis , at the top edge of the firewall.
if you want....