The oil pressure sending unit needs to match the ohm of the gauge. The sending unit is a variable resistor. I'm not sure what the ohm measurement should be. But it should be listed in the first gen manual we have in the manual section.
To use the sport cluster you just need the cluster and there should be a plug under the dash already there.
If not you you just need to run the wires down. That info is in the first gen manual.