Australian Car Repair Issues? Ask an Auto Mechanic for Answers ASAP
I have done a similar conversion VN/VP wiring into VB Commodore.
355 stroker/ 4L60 auto.
You need the O2 sensor.
You need an inline VSS (vehicle speed sensor) fitted to your speedo cable.
And then you need a "magic box" between the VSS and the ECM.
The factory VSS signal goes to the instrument cluster first for displayed speed, the signal goes through a divide by 5 counter and then to the ECM. The ECM needs this to control the IAC so the car doesn't stall.
I would contact Castlemaine Rod shop:
Hope this helps.