1. i dunno
2. your 5 speed manual w56b will work just fine. will need a bellhousing adapter though. the gm 4.3 has the same bolt pattern as the small block v8.
3. if you can fit the chevy radiator that would provide you with more cooling capability.
4. your toyota one will be sufficient, but the gm pump is much more powerfull if you ever go with hydro assist or a hydraulic winch.
