Ponyboy is saying that the Socs are really drunk when he describes them as “reeling pickled.”
The term “pickled” is often used to describe someone who is very drunk. A person who is drunk is disoriented, which is a feeling described as “reeling.” Therefore, someone who is “reeling pickled” is very drunk and disoriented.
Pony describes the Socs as drunk and “staggering.”
That scared me. A cool deadly bluff could sometimes shake them off, but not if they outnumbered you five to two and were drunk. (ch 4, p. 55)
Johnny was also “scared to death,” and while Johnny had a switchblade knife Pony did not have anything to defend himself with. Soon the Socs had them backed up against the fountain. Johnny had to act to defend them, and killed Bob.
Later, Cherry explains to Pony how she can’t forgive them for killing her boyfriend, but she is aware that he was a mean drunk. The fact that the Socs are drunk makes them more dangerous, not less so, because they have even fewer inhibitions than normal. They think about hurting greasers, without factoring in the societal consequences.