i am looking for the correct bolt size for a 70-71 duster trunk lid. the bolts that i need are the mounting bolts from the trunk hinges to the trunk lid. does anyone know what bolts i need also the size?

thanks nick

69 Barracuda might be the same.

4 pcs indented head hex machine screws, size 5/16-18 x 1-1/4, 1/2" across flats, 1-1/8 conical captive washer. Originally phosphated with body paint on head. Maker's mark "GL".

Exactly same as part B-11931 on page 105 here, except length and maker's mark:
http://www.amkproducts.com/Catalog_PDF/92-108.pdf

I'd say if you can find the original impression of the washers, and they are 1-1/8" OD, then this size fastener will be correct for you.

Special captive nuts are spot welded or crimped to a sheet metal insert that fits into the square tube hinge. If you don't have the special nuts, you can fab something similar - this part is hidden. If you need a photo of the nuts, PM me, and I'll make a photo.