Steve DeL---Taking things in the order that you presented them:
1) Oil passage down the valve guides is symptomatic of worn guides in
any engine when the miles start to pile up. It may start to show up a
little sooner in the TR because-
2) No valve guide seals were provided in the original head design.
3) I prefer replacing the guides with the ones made from a bronze alloy.
Some of the Big Three offer these along with the std. cast iron ones.
4) I don't think the '71 has the 7.75:1 compression ratio, but rather
the 8.0:1. If you want to take this down to 8.5:1 it is necessary to
mill the head to a thickness of 3.460, according to the Comp. Prep.
Manual. The math here isn't moon-shot accurate, but it looks like the
compression ratio goes up about 1.0 for every .060 taken from the head.
In the event your head is as the early engines, that being 8.5:1, you
may already "be there." Measurement is as before the defining way to
You feel that the fouling of three of your plugs are from "oil." This
could very well be the case, but carbon fouling can also be from excess
fuel from one of the carburetors. This fuel fouling could be if the
three fouled plugs are the first three or the last three. (You didn't
say) If it's definitely an oil fouling, this will show up with tell-tale
puffs of smoke between gear shifts, or any time the engine is
decelerating. A friend following in another vehicle can verify this.