I just got through installing a DW kit that came with my new Z that the previuos owner supplied. I purchased new style 740's and a new EFI harness. The Z1 kit the caps are different. Z1 uses a new machined cap vs the adapted cap from DW. So after all it may be doable but I still see the same clearance issue. Although the Z1 kit is simplified with less hardware over the injector, the adapter will still position the injector and cap higher out of the rail and may still present an issue with tooling access to secure the cap screws.
It may be worth a shot... plan A, but for all the reasons stated earlier pull the plenum and refesh all the rubber which comes with piece of mind... plan B.
