It depends on the width machine, but you can adapt to 5088, 6088 and 7088.
To suit 1020 - 17.5, 20 and 22.5' versions you need
87667737 Elec/Hyd Adapter kit
87336803 Sliding pin latch kit
87473650 PTO shafts
126012A1 Slow down pulley
87374406 Combine Feeder Face
To suit 1020 25 and 30' versions you need
87667737 Elec/Hyd Adapter kit
87336803 Sliding pin latch kit
87473651 PTO shafts
126012A1 Slow down pulley
87374406 Combine Feeder Face
The only difference in the two is the PTO shaft part#
Hope this helps - not sure on prices contact your dealer - that's what they're there for!