You can use a DFSORT job like the following to do what you asked for. I assumed your input file has RECFM=FB and LRECL=80 but the job can be changed appropriately for other attributes.
//S1 EXEC PGM=ICEMAN
//SYSOUT DD SYSOUT=*
//SORTIN DD *
//SORTOUT DD DSN=... output file
//SYSIN DD *
* Put special key of '1' in 81 for data records.
* For header record, put special key of '0' in 81.
* Sort by special key ('0' or '1') and then regular key.
* Remove special key.
For more information, see the "Sort records between a header and trailer" Smart DFSORT Trick at: