F70, anything larger than an "F" profile bulged on a 7" rim, that is why the 1970-1973 Z28 (and I think the Trans Am too) came with the F60 as an OEM tire (on the stock 7" rim).
The Corvette used a G70, but they were on a 8" rim.
That is my answer to your question and I am sticking to it.
