Carb question stock 340

When I played around with the 650 versus the 750, both Holley dp, I found that I gained just a hair more grunt down low but gave up a lot of power after 4,000 RPM and I have a stick car...so that was a dead deal. 750 won.
I'm not sure it's worth the money for that amount of low end pick up to switch to a 650 for you, I persoally might put that money into headers, Gears or better heads/intake manifold 1st. More info could be useful.