Bang for the Buck Thread

If you knew eventually the end goal was to have a stroked 408 with better heads roller rockers ext, do you still think the heads would make the most difference in the short time? My budget will probably allow me to spend about 3000$ a year on car upgrades. So whatever I do to it, it will have to go a full driving season with just that.

Love hearing everyones different takes on things.
I'd get the top end with the initial $ 3000.