I plan to install front seat 3 point restraints. I will mount the upper point at the top front of the rear side panel just behind the door jam. I hope to reinforce the inner side of the metal to counter the force in case of an accident. Any ideas how to reinforce it???

I know its a safety thing but how is that going to appear to the eye? What vehicle are they out of?I'm just going with a lap belt I think from the link below.
I would like to hear and see how you make out with the 3 point keep us posted.

On a 67 they don't have the bolt holes for the 3 point is your problem correct I think the 69 has a heavy bolt hole up there but I still am wondering how this will look...

http://www.speedwaymotors.com/p/7344,636_Lift-Latch-Lap-Belt.html?itemNo=seat%20belts