When Red and Eric were talking in the driveway there was a van right next to them. The tail lights shown on that particular model van were only produced in the mid 80's and later.
Chevy van rear lights up to 1985 were recessed:
Chevy van rear lights 1986 and later were 'bubbled' (as shown in this episode):
These picturess are not the best way to show this, but it can be seen that the lights are clearly different, and it is obviously the latter style that is used in the show. How can a mid 80's van be in a show about life in the late 70's?
Eric: Jackie, why don't you ask Hyde to help? Oh that's right, he's your boyfriend. I guess that's punishment enough.
Red: What's going on?
Kelso: Oh, just a classic case of hand stuck in vase.
Red: Well get it off. Or you'll have a classic case of foot stuck in ass.
Red (to Hyde about Jackie): Whatever happens, you're driving her back. She talked so much on the way here, I thought I was gonna have to strap her to the hood of the van like a deer.
Hyde: Hey, what does the tiny writing on that vase say?
Kelso: What tiny writing?
(Kelso brings the vase close to his face. Hyde smacks him with the vase)
Kelso: Stop doing that!
Hyde: Get smarter!
Kelso: ...Last time I was here, I hid a stash. I just need to remember where it is. I know it's someplace I can fit my hand.
Hyde: Well, that rules out your face.
(Kelso puts his hand up to his face; Hyde smacks it into his face)
Hyde: Hey that vase smells like chocolate.
(Kelso smells the vase; Hyde hits it into his face0
Kelso: You can't see it, but I'm flipping you off right now.
The show is now aired on Wednesdays.