I think the reason for block the EGR valve is to prevent the carbon build up in the intake. This build up can cause air flow or bent rod problems. To be or not to be, search the forum for the related subject to make your own judgement call.
All 60x engines, started as early as 1984 on 190D, do not need valve adjustments. Correct me if I am wrong.
[This message has been edited by be459 (edited 04-22-2000).]