Holley 390 4bbl on my slant 6?

What model holly 390 ? They all are like 2-3 times cost of a holly 450
I have a holly 450 and a edleb500 . Everyone on here said 390 was too much but best but that 450 and 500 are way way to much so I have hooky on there . I don’t know what model . Old Ford Mustang 390 I’m pretty sure . . Either way stock slant 6 with headers and large square Clifford 4bll intake . But stock cable can’t mount and is to short . So looking for what is needed to hook up to any of the the 3 4bbl