Irishair2001
I think you may be mixing up your DC-8. There have been 2 parked on the remote stand at Jhb recently.
The one that is still there is a DC-8 63 series and that has its reverses deployed.
The other a/c that was there was a DC-8 72 and it has CFM engines. These engines are the same type as on the 737-800 that SAA operate. When the thrust reverses are deployed on this a/c a sleeve type mechanism slides rearwards. Looks like the engine is splitting in half. Nothing is deployed at the back of the engine as seen on the 737-200 engines.