I guess I said that wrong. Three types explained. Even though this isn't for FORD they follow the same basic principle. I have the Single plane since it allows the fuel mixture to be drawn from side to side if demands need it and that allows every cyl. to have a better chance of getting the best mixture. Most racers that i know have the single and they also use it on their street machines. Most of the problem that people encounter is that they over cam and that looses your bottom end. I did that with my mustang.