Bacchanal

This has been bothering me lately, and I hope someone here can help me out.

I remember when I was younger seeing a movie, but I can't remember much about it. I know it was made in the 70s/early 80s and the main characters were teenagers.

-What I remember most clearly is one character has a weed leaf belt buckle, and tells someone else that it is a poison ivy leaf (this sticks out because I thought it was true, and didn't find out different until I saw the same belt buckle and pointed it out to my dad. OUCH).

-One character got jumped by at least two guys at a playground at night.

-I think one of the character's dads was a car dealer.

-At one part some teenagers are in a house (possibly abandoned) and one of them shows off that he has a gun.

-At at least one point in the movie the teens are in like a Boys Club type place. I can't think of the name for it, but a place designed to keep kids from "getting into trouble", ran by adults, and has games and whatnot for them to do as opposed to "running wild". Basically a place where they're under some kind of supervision.

Anyway, it isn't a big deal. This has just been bothering me lately, and I wouldn't mind seeing the flick again, honestly. I know I watched it a few times when I was young, but I can't for the life of me think of what it is called.

Thanks in advance for anyone that can help!