Replacement Springs and Bars

I have a '71 Demon that I plan to turn into a small block cruiser (currently has /6). She's all original and a runner, but needs the springs and bars replaced asap.
Thinking about the .920" bars or possibly the 1" ones from Just Suspension. My dilemma is that I plan to run the /6 til I can afford the small block. Would either of those bars be too stiff for the 6?
About the rears: I've read multiple posts about peoples issues with ride height. I would like to keep the body level, without the "hot rod" rake (just my preference). The body is unmolested and would prefer bolt-in replacements without modifications.
Price isn't as big a concern as having them fit right the first time. The Hotchkis springs are pricey, but as mentioned people have had issues with other springs.
Any input would be appreciated.