Social security

What amount does surviving spouse when other spouse dies? Simple Example: (numbers made up so may not make perfect sense) Married 40 years, both 74 yrs old, surviving spouse collecting 500.00/mth in social security, deceased spouse had waited till 70 to collect and was getting 3,500.00/mth, it would have been 2,800.00 of he would have collected at FRA. Does surviving spouse start getting the delayed amount (3,500.00) or would she only get the lower FRA amount (2,800.00)? Thanks!