We were given a free Karmen convertible Bug a few years ago.
The car was almost 1500 miles one way, at the time we had an old Wagoneer that was using a Lot of oil.
At our first gas fill up it was down by 2 quarts, we bought some Restore dumped it in and made it to the destination 1200 miles away using just over a quart. Changed oil in Tucson and added another can of Restore and made it back to home 1475 miles flat towing the bug behind us Wagoneer used 1 1/2 quart on the trip back. So a 3000 mile personal test
Project Farm also had good luck on an Old ford diesel tractor using Restore and also verified the compression increase.
I do not recall saying it would rebuild an engine.
The Project Farm engine was so tired it would not start below 90 degrees before adding Restore
A year Later...
ps. Added Restore to my recently purchased tired Ford 550 TLB and when we originally went to check it out, it had trouble starting at 58 degrees. I put Restore in with T6 when I got it home and changed the oil,
This morning it was 39 degrees and freezing rain, the 550 fired right up with no thermostart in under 10 seconds. It also worked well in my old 3000 Ford also a very high hour engine.