Which intake should I use/ buy

Since you say this is a street car with occasional forays to the track, a dual plane manifold like the one you have on it offers better low end throttle response (where the fun is on the street). The dual plane manifold is split in two (see divider under carb) and each half feeds 4 cylinders. A single plane manifold has one big hole under the carb (Torker is an example) and it feeds all 8 cylinders. Single planes are more effective at higher RPMs and less responsive at the lower RPMs that you usually drive on the street - that's why they are preferred by drag racers who keep the RPMs up all the time, and dual planes preferred on street cars.