Best stick with Lamar. He's the safest candidate.
I'll assume you're not from TN. You're talking about Shelby County (Memphis). No conservative is going to have a strong following there. But statewide is a different story. As someone else pointed out, Tennesse is three areas politically. East TN is solid, reliable Republican. Middle TN in a toss-up trending only slightly (very slightly) toward Republican in the last few years. Then there's West TN, and more specifically, Shelby County. It's solidly Democrat. As you go outside of Shelby County in any direction, it's mostly conservative (blue dog) Democrats.
Democrats haven't fared very well statewide in TN for about ten years.
Furthermore my family, as well as many others I know in Shelby County outside of metro Memphis, will literally crawl to the polls to vote for anyone who runs against Harold Ford, Jr. His family's brand of politics does not sit well with many of the Tennesseans I know. Memphis is not the hometown I fondly remember--and the Ford family is a major cause of my current disillusionment. Sensible folks in Tennessee feel the same way.