can you turn the engine over with a breaker bar and socket on the crankshaft pulley bolt?
i'd guess you can, since it's in the car and i assume you were able to spin it over to put the torque converter bolts in, and even a weak starter makes a lot more torque than you do..
check your connections- the hot cable tells me that it was drawing too much current.
how big are the cables, and where are they hooked up? cables should be at least 4 gauge and the ground cable should go directly to the block.
is the starter good? just because it's new doesn't mean it's good.
does it crank over better if you pull the ign fuse in the fuse box to disable the ignition?