if your transmission is from 88 then your stuck using 88 d series clutch/flywheels
also, an OBD1engine harness does not plug into the OBD0 firewall harness, they have different plugs.
You can alleviate some of the distributor leaking with either a new o ring on the dizzy and possibly some RTV seal on the old one, but its not really the best of fixes.