I Don't know if its been done on tractors, have heard of dodge truck owners with the bosh VP44 inj pump swapping out electronic pump for mechanical pump. Is this possible with tier 1 and 2 tractors like 7320 and 7420 with level 4 (VP44 pump) and 12 ecu (standadyne DE10 pump)? My only concern is will this mess up the canbus if you elimate the ecu and still have the other controllers that communicate back and forth? Why would I do this you ask? simplicity, reliability etc. simple repairs and fewer wires to break/chafe. Would need to gear up mechanical linkage to foot and hand controls. Maybe its not worth the effort but seeing if anyone has heard of this being done?