Well I didn't get the trans separated yet, but I measured the F2 and F6 crossmembers. I could explain all of what I measured, but I'll sum it up as this. The T98 was optional for the F4, F5, and standard behind the big 6 in the F6. Crossmembers between these and F2/3 are different, but only in height due to frame height, but the engine perches and cab still sit on the top equally (F6 c-memb drops lower). The trans mount that holds the speedo cable and 5 bolts on the back of the trans appears to be the same between my F2 crashbox 4sp. and the T98, except in mounting height (the cast ears are different, such as the F1 sits nearly even with the output shaft). So I think by using the F2 transmount bolted to the T98, it would fit in the F2. Someone else may want to chime in if they know for sure.
EDIT: At some point that I remove the trans mount parts from each trans, I can then compare them side by side.