Update & 3-point seat belt system?

['70GMCStep]

Been a long time, nice to be back.

My '65 c-10 is almost done mechanically. 350 crate with RV cam, 4 BBL edlebrock with alumin. intake, HEI dist., rebuilt 700 r4, front disc brakes with powerbooster and tubular control arms from CCP, rebuilt rear drum brakes, frame grinded painted, underneath truck undercoated, cleaned up/painted exhaust maifolds etc. Put in a different, cleaner gas tank and sending unit, and coated the inside of tank with sealer.(Body is next after I save some more) Learning as I went with advice as I went along.

BUT, now that is almost ready to put back on the road, I am thinking seat belts. How big of a mess will installing a 3 point seat belt system be when it didn't come with one. Any suggestions for parts, tips etc.? I want to be able to take the kids down the road in the rig and feel safer.

Thanks as always,

'70 GMStep

'65 Chevy c-10
'70 GMC stepside