Check your alignment of the gas block over the barrel port, you may need to slide it fore/aft or roll it.
This, it sounds like you didn't get the gas block aligned.
With the screw backed out (not removed) from that Seekins block, it functions the same as any other gas block. It won't restrict the gas any more than your original gas block did. If you have function problems after installing it but not before, then most likely it's an installation issue.
