<VV> NON Corvair - blown head gasket advice needed

[Kinzelman, Andy]

Guys,
I REALLY need an extra running car for a while.
I have the opportunity to get a good driving car with a blown head gasket; that is NOT economical to repair.  Assuming I could get it for its (non-running) salvage value - how long do you think I could drive it locally before it expires from the blown head gasket?
Thanks,
Andy K.
Wisconsin