When I upgraded my 77 300d, I saw no reason to replace the OE relay and timer. I put in the new plugs, wired the one nearest the firewall the same way the old set was, disconnected the ground wire from the front plug and put the jumper wires between the new plugs. Been working fine that way for 6 yrs.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13