In large pot of boiling water, cook potatoes until tender; drain. Cool slightly; peel. Cool to room temperature; cut into 1/2-inch cubes.
In large bowl, combine SPAM® Classic and potatoes. Add carrot, peas, pickles and onion; gently toss.
In separate bowl, stir together mayonnaise, pickle brine and mustard; gently stir into SPAM® mixture; cover. Refrigerate several hours before serving.