You'll need to change the sump, pickup, mounts, dipstick and exhaust manifolds to suit HQ-WB.

Plus you'll need WB V8 auto radiator and hoses, throttle cable, exhaust and battery harness. The VK engine wiring harness should just plug straight into the WB's cabin harness.

For the VK trimatic you'll need a TH400 T-bar and shift rod plus WB V8 trimatic fluid lines.

You'll need a HQ-WB V8 ute or van diff as well.

Plus a tailshaft from:

HQ-WB 253 ute or van (or 308 manual).
HQ V8 Statesman (not 350).
HQ V8 wagon.
HJ-HZ 253 wagon (or 308 manual).
WB Statesman with trimatic.

You will be able to get away with the WB 6cyl diff and tailshaft but they are not right for a 308 and will easily break.

Pollution equipment will basically hook up readily from the engine to the WB canister.