The original belts may safe your life, or do some severe damage to your hip since they are not retractable. The problem now is that the newer technology in new cars and the impact design standards make it even less safe to be hit in an older car. To really be safe in an older car you would need to strengthen so many areas, just really not an option. Even if you have up-to-date seat belts you will be more likely to be crushed because the car collapses inwards and does not have any crumple zones like the new cars do. My opinion, you are still better with the seat belt than without, but the cars are not even close to being safe. Frame ties are a nice start to bracing the car better if you don't care about losing the stock appearance.