Small block 400 just isn't enough....?

[Hazieview]

Okay fellas I have a small block 400 with a 350th trani and I think .308 gears. My sb400 has a mild cam, performer edelbrock intake, 600cfm edelbrock carb, and dual flowmasters. I dont have performance heads, headers, nothing like that. Only what I listed.

Guys it just aint enough power for me. I thought about getting some edelbrock heads but, for $1,000 or more, how much will that even help me?

My 3 speed 350th trani as we all know shifts really quick so by the time you hit 70mph your running some pretty high rpms as it is.

My .308 gears dont let me leave near as hard as my old .373 posi rearend did which really sucks.

So what should I do? Throw some more money into the engine? Swap my trani for a 700r4? I'm trying to be realistic so where would my dollar be spent in the wisest way?