This may sound kind of silly, but, have you tried changing your blocks orientation?
Most block companies suggest orienting their blocks so that the fittings are viewed as standing one above the other. From your pictures it looks like they are side by side.
If you have tried everything else, flushed the rad, checked tubing for blockages, then try rotating your block.
Edit: alternatively, open your block and make sure that everything is inside properly, as jet plate, gasket, correct orientation of finned bottom, acording to the blocks instructions
Edited by NimbleJack - 7/10/13 at 5:22am