340 No low end power

So... trying to keep it simple and work my through, start with..
Get the timing dialed in, find out the gear ratio and converter, upgrade the manifold and then the carb if needed? I do have some options, I have a set of 1970 T/A ARR heads, rockers etc but it doesnt sound like it will help much and I was going to sell them to pay for of the upgrades. I also have the stock intake manifold and I think it has an Edelbrock carb on it, not sure of the model and I'm sure it would have to be rebuilt so using my existing carb would be prefered or am i wasting my time with either? I also have some Thrush welded 2 1/2 mufflers but really dont want to change the whole exhaust system if there wont be that big of a gain. My ultimate goal is to have a nice driver, good power and sound. The thing sounds like it should be shooting flames out the back when you get on it but from a light it cant even brake loose, let alone get out if its own way.