In my best Beaver Cleaver lingo, Golly gee whiz, Uncle Bob! That's really neato - no cooties in that! Did you see that on Mr Wizard?

One issue is that I already have my seats of choice (Fiero), and I've got the reinforcing plates made to go under the floor pan tying them together, along with the seat belt mounting bolt locations, so shopping for different seats is not really high on my list. I'm pretty sure that I could figure out an upper mounting method to "engineer" into the top of the seat back, but the seat frame is not designed for that load, so the real "safety" would not be there, and it would actually be less safe than lap belts alone. I'll look at the angles and heights a bit more, but I'm pretty sure that lap belts are the only answer given that I'm not changing the seats.