Engine change-over?

immobilizer is seperate to the ecu on the astras so dont think it will be a problem, as long as the blocks are the same and use the same mounts then you should only suffer superficial problems like having to replace a hose for a longer one or cut it down shorter maybe cut and weld the exhast downpipe etc all of which is not a problem for a competant mechanic/engineer so it shoudln be a problem, also are you using your original gearbox or the isuzu one because again unless the block is the same your astra one wont fit. it is best to use the isuzu clutch if possible as the crank my be different but again this may not be the right depth for the astra gearbox. its a case of getting the engine out and split down then see what you have. to be honest unless you have thrown a rod through the block it may be better just to rebuild your engine rather than **** around changing it. labour will be about the same anyway all it is is parts but then it gives you peace of mind nowing the internals are new/ish