rear end thud?

[drmuddle]

Hi, i've now completed my engine rebuild, all works fine but i notice that when i accelerate hard from stand still there is i thud as if an engine mounting is worn? whilst the engine was out i decided to renew the 2 mountings that are attached to the convertor housing.
Any ideas what this is?
It was starting to do this before the engine rebuild mainly on hill starts which was the reason of changing the 2 mountings(they were split!)
Many thanks....Nick

[JOSEPH A. POPEK]

check your rear hubs. they should be tourqued to 300+ ft lbs.
or it could be your vaccum adjustment  is still to slow. its hard to say with out hearing the noise.