How long is a piece of string? ...depends on how bad your motor is and what sort of outcome you want. Anything decent and you are looking at about $2000 minimum so it can be good sense to get a 2nd hand one from the wreckers or someone selling privately. If you can do the labour yourself you will save heaps. The other thing is that reconditioning the motor may not be the end of it - you'll probably need a new radiator, starter motor, waterpump etc etc.....and they alone can add up $1000. So its best to figure exactly what you want then do your sums.