Isuzu Repair: Nissan Pathfinder Wagon 1989, holden commodore, nissan pathfinder

Question
Hi Daniel,

I have recently purchased a 1989 petrol Nissan Pathfinder which has had a Holden Commodore 3.8lt V6 engine fitted to it. I am in Australia and believe that the Nissan was built in Australia.  The engine is reving a little high, and I want to change the diff ratios to help correct this. Holdens run a 3.08 diff. Is there any thing known to be compatible.  It also tends to run a bit hot and I'm wondering if a V8 radiator might help this.  Thanks for your help.

Answer
Well Keith. I would probably install a transmission cooler, and maybe a dual fan unit as well for the engine with a coller thermostat. The revving is probably due to a fualty choke control valve or leaking vacuum somewhere. Spray around the intake manifold with some carb cleaner and if the revving problem stops. their is your problem. Also check all your throtte linkage as well. Let me know how it goes ok?