which purge kit, -6AN or -4AN?

[andrew N.]

did some looking online, didnt get a straight answer.

[John_D.]

I think most of the kits for our cars use the 4 size. The nitrous lines that is. The blowdown tube is larger.

AN sizes are in 1/16th's of an inch. (that's the outside diameter)

Here's a link that shows some corresponding info for different AN sizes. It includes a picture at the top of the page, with different AN fittings shown to scale. That may help you confirm the size you need.

http://www.anplumbing.com/thread.html

[12secondv6]

Bigger size is louder and thicker but short clouds....
Smaller size is quieter and thinner, but taller clouds

[John_D.]

Oh, I understand the original question now... :D