I don't know what polls are showing but I can tell you that election returns -- the only polls that count -- are definitely NOT showing blacks supporting pro-life candidates!
There's a very, very, simple reason why that is so.
Allow me to explain. I was talking to a black co-worker a couple years ago (I'm white.) I knew she was a conservative, but also knew that she voted Democrat. I asked her a series of questions - her opinion on abortion, the death penalty, gay marriage, entitlements, and even affirmative action (though I will admit to phrasing it as whether or not she thought one group of people should get special consideration due to skin color). In each instance, she responded with the appropriate conservative answer - anti-abortion, pro-death penalty, anti-gay marriage, etc.
Then I told her that I had just outlined the Republican Party's position in a nutshell, and that the Democrats generally believed the opposite on each one. Then I asked, in light of the fact that she obviously agreed with the Republicans, why she would vote Democrat. Her answer stunned me.
"Because Republicans don't like black people."
That one, single sentence is why the Dems have 90% of the black vote. They've convinced the African American community that, regardless of what else blacks and Republicans may agree on, that conservatives don't like black people. When we as conservatives change that perception, blacks will flock to the Republican party in droves.