It was indeed a storm brewing and it has come to a head. My original idea was to just put it back together with the F intake/exhaust manifolds, but that was complicated by two stripped/cross-threaded bolts at the heat riser. One was not possible to remove (I tried really hard for hours.) and the other had maybe 4 threads at the bottom of the tapped hole in the intake. Since this is an exhaust pressure chamber I did not want to try to run with 1.5 bolts out of three...so, I gave up and am dealing with the header. It turns out that some model year 2F had an aluminum oil filter mount with the sensor tapped but no oil cooler plumbing (that is a can of worms!). I ordered one from Spectre and have started trimming up the header and intake to fit the gasket. Only had to trim one half-hole on the header to get 12 mm bolts to slide in. I am guessing (WTF?) that Toyota didn't use studs for the 12 mm manifold bolts because of issues with tightness with multiple components, so I have looked for internal hex bolts but to no avail. I have seen Toyota bolt sets for the larger bolts and will probably use these with some trimming of the aluminum intake manifold to fit; with respect to the obvious mismatch in thickness of the aluminum and steel components, I will cut 1/2" grade 8 washers (they are the smallest in outside diameter) in two to make "step washers"; this seems the correct thickness; everything should be fine from then on...at least it is a WAY FORWARD!