If it is going in a HQ or HJ the advantages are you can do what you want as long as you keep the PCV system (injected motor has this) and a canister recovery for fuel tank vapour on post 1/1/75 vehicles. So no Engineering, no cats, no filler neck etc. It all bolts onto any 308 block, you just have to use an EFI cam and not a VSIII/VT roller cam. No goof for a HX coupe though as in these you have to use the whole injected motor and get it Engineered.