I unplugged my seat belt plugs right at the trans tunnel for 20 years. 10 years ago I rewired the car and put it back in working order. Got to be careful if you got something heavy on the pass seat as it won't start unless you plug in the seat belt on the pass side.

I use my seat belts now a days so it don't bother me much.

Make sure it's not the nutrel safety switch giving you trouble and not the seat belts by temporary jumping the starter relay to ground to eliminate that.