Dave Plowman wrote:

Early TCs had a high compression ratio designed for 5 Star, but then so
did early V-8s. And IIRC, the compression on the four is determined solely
by the pistons, and the TC was certainly still made after the change to 4-
Star only.

This is a 2000TC from '72. Would it be the 2200TC (from '73 onwards?)
that came after the change to four star?

Yes - it's pretty smooth. The first place rust usually shows is inside the
car at the joint between the floor and sills - you'll have to peel back
the carpets to check. Many are crudely plated here. The other thing is the
original jacking points. If these are sound, there's a good chance
everything is. Few bother to repair them even when doing a 'good' job on
the inner sills.

I peeled back the carpets as much as I felt I could with the owner
watching. What I could see looked sound, so even if it does need work,
it should be well within my capabilities (I hope). One visible area of
rust was a small hole below the pedals. The dented floor adjoining it
suggested some twit had tried jacking it there.
The cover sills and jacking points looked pretty horrid. If I get the
car, I won't be able to resist removing the covers and investigating
before long.

I suppose the other way of looking at it is, how many cheap examples of
P6s are likely to be sound in these areas? The last one I looked at
properly was a friends 2200TC when it was about ten years old!