The 4L60 is a 700R4, just with a new updated name.
4L60E is the electric shift, solenoid controlled valve body version of the 4L60 (no more TV cable).
The V8 bellhousing to block pattern is the same from LT1 down to first gen blocks.
In 1996, the trans was changed to having a removable bellhousing, but main body of the trans innards is still the same.
The bellhousing on the LS version has a different trans to block bolt pattern.