Simplicity 5450 vintage sewing pattern, dated ca 1964.

Women's Jiffy One-Piece Dress or Jumper: Simple-to-Sew.

The A line dress has a slightly scooped neckline and darts at front underarm, back waist and back neckline. Back zipper closing. In V. 1, a large patch pocket is detailed with a button and top-stitching trim which are optional. A purchased belt may be worn in V. 2. 

Size   42:

Bust  44 inches / 112 cm

Waist 36 inches / 92 cm

Hip    46 inches / 117 cm

Pattern is UNPRINTED, factory pre-cut tissue pieces with perforated symbol markings, checked complete and in good condition. Envelope has some staining in some areas.

More '60s patterns here:

http://allthepreciousthings.com/collections/1960s