ilovefuzz.com

I don't know anything about this stuff. I want to replace the tuners in there right now.

I want some tuners that will drop straight in, how do I make sure they're the right size?

Klusons SHOULD fit right in.
http://www.wdmusic.com/shop_by_category_tuning_machines_kluson_3_per_side.html

Grover Vintage SHOULD too.
https://www.grotro.com/Grover/VINTAGE

I just bought some of these for my SG Faded and they work great.

http://www.guitarfetish.com/3x3-Keystone-Green-Key-Vintage-Style-Tuners-Nickel_p_36.html