How do you replace a harmonic balancer in a corvair?

I have a 66 Corvair with a separated harmonic balancer. There is only a few inches of clearance between the bolt and the body of the car so there is no way to get an impact wrench in there. I was told that I would have to raise the engine out of the car in order to do this! Is that the only way, or is their another way that isn't this invasive?