Longevity of 2.2 motors

Alright here is a crazy one. I have a 70T that had the motor rebuilt in 1978, as best as I can tell motor has about 175,000 miles on it. Motor leaks down 1.5-3.5% has excellent oil pressure and runs fantastic, leaks or burns no oil. Is this possible or has motor been rebuilt the interm and I just don't have paperwork. Also when motor was rebuilt the P&C's were replaced with some very expensive for the time P&C's, I assume they were 2.7 Mahles, which might account for the longevity.
Thanks,
Phil

I would tend to think you're missing some paperwork however, with the right care... anything is possible. I would think the 2.7's and the extra heat generated migh "hurt" the longevity.

I can't recall Bruce's figures but, it's something like this:

Bottom End Good For - 130k (main and rod bearings etc.)
Top End Good For - 70-80k (rings, valves, valve guides etc.)

Experts weigh in... those are just faint memories in my aging mind.