a y8/y7 oil pump.
but, i don't know if it will fit a d15b7 block.
then you will have two dipstick holes...
also, some people have drilled and tapped their block for the knock sensor.
watch where the metal shavings go if you try that.
or, depending on what state you live in you could do an obd1 swap.
get a p28 ecu and an obd2b/obd1 conversion harness.