Datsun 1600's are assembled using some common sized metric bolts e.g M5, M6 and M8 etc.
It would pay for yourself to buy a cheap set of vernier calipers which you can measure the inside diameter of the holes to see what bolt/screw size you require.
Headlight bolts are M5x0.7mm pitch and approx 12mm long.
Front mouldings are held on with self tapping screws. Dont know the guage of top of my head but I usually just measure the hole and buy screws to suit from a hardware shop.
Bonnet mouldings are the hard bit they have very short self tappers.
Its easy to put too long ones in and dent the moulding from the inside with the tip of the screw.
These screws are only 5 or 6mm in length and require a small washer to mount/space them correctly.
Dash from memory is M6x1mm pitch and approx 12mm long.
Doors and bootlid are M8x1.25mm pitch and approximately 16mm long.
Bonnet is M6x1mm pitch and approx 16mm long.
p.s. last time I was at Datport they had buckets and buckets of replated/new bolts there and may sell what you need.
Personally id raid a pick-a-part style wrecking yard and grab what I needed as lots of cars use similar mounting hardware...
You sir are a legend! Very helpful info. I do have some bolts was going to go to a bolt shop and get some new ones or see how much they cost as my old ones aren't in the best shape.
It is just the front I need examples of if I knew what to get it will be no issue, but I will look at that tool you said and try to measure the inside of the holes etc.
Thanks a lot for the info again, great help