sorry i cant help with the granny but im doing this to a saph
so i'll be checkin this thread
however i do believe the bottom end of a 2.8 is the same as a 2.9.
ford sent batch's of them to cosworth for improvement, longer stroke on the crank gave more capacity, and the heads were changed along with manifolds.
ive also heard that the better thing to do is use a bob bottom end and boa heads with bob cams but this is a lot of messin around.