OK - hydro boost just rebuilt my booster.
Mine was broken around the bakeite (if you have the piece that's missing, they can repair it)
BUT
As Barry said, the '69 and '70 boosters are different, and it's VERY odd for the bakelite to break UNLESS a '69 booster has been installed into a '70 car (or a '70 car with a '69 pedal).
The correct booster for a '69 has a shaft that looks like this -concentrate on the shaft that attaches to the pedal:
Whereas a '70 booster has a shaft that looks like this:
you don't want to bolt it all together and break the new one on the first brake application, do you...