i believe that a vortec engine has the same block bolt pattern as the older ones.... but the newer engines (LS1 style) have a different bellhousin pattern then the older ones.....
a 700r4 would work in place of the 4l60e though, as far as boltin up to the engine
Looks like not - the tailhousing pattern changed when they went to the removable bellhousing... AA has kits to fix that, but it takes the "affordable" appeal out of the equation.