1997 chassis has about 240,000 miles.
The original engine failed at 204,000 street miles. Then the car was re-built as a race car and a used replacement engine installed.
The current engine (#4 since becoming a race car) has around 100,000 street miles plus another 70 hours racing. I don't know the conversion between hours of racing and equivalent street miles but my guess is that the 70 hours (near or at redline) is close to another 70,000 miles on the street. With 70 hours racing already, I expect it to fail sometime in 2018; but who knows, maybe it will make it to 2019!