May be a dumb question, but without a body manual or a lift, I hope someone can answer prior to me tackling seat belt replacement.
Re: standard lap belts on 68 convertible:
Does the outer belt with retractor bolt into a fixed/welded nut in floor/frame or is there a free bolt that I need to find somewhere under car (I can not feel one or get my hand anywhere near where I think it might be)? In other words can I do the replacement all from the interior or do I have to get under car and possibly remove something to access nut?
Then does the inside belt do the same or is there a nut in the tranny tunnel that I have to access from under the car?
Any pictures from a body manual would be greatly appreciated.
Thanks

There are special sholdered and treated bolts that mount all the seatbelt anchors into the car from the interior side. The heads are fairly large, I am going to guess from memory and say somewhere on the order of 3/4 inch.

You will have to pull the rear seat bottom cushion out for sure and it might be much easier to pull the front seats out too. Pulling the fronts will make both getting the rear seat out and access to the front seatbelt bolts much easier.

And I strongly recommend investing in a set of factory service manuals.

Everything can be done from inside the car, no need to get underneath the vehicle.

thanks, what I needed to know

The only thing I would add is you may want to access the rear bolts from underneath in order to spray (WD40 etc.) the bolts as the ends are exposed (rear seat belts) between rear diff and rear floor pan.

The bolt(s) could be fused to the body panel nut(s).