Will a 4V air cleaner work on a 2V? I hope so cus i got it over the net and I opened it up and it was bigger that i thought and to my dismay it read 289 4V. Please tell me theres a way to make it work =(.

Brandon,
The first thing I need to know is what year is it, there where no 4V 289's in 68, so I assume it is for a 67 or newer which would make it incorrect for a 68 GT/CS. If it is actually a 68 289 with a 289 4V sticker on it, it will fit. I believe the 68 289-2V and 302-4V aircleaners can be used on either carborator, there is a difference in the size or the opening of the snorkle attachment to the heat riser. I can send you a pic of the correct aircleaner but I am at work so I have to wait until I get home.
Doug

The Air Cleaner is pretty big maybe a picture will help are the dimensions between the 289 and 302 air cleaners different?

Brandon,
I believe the are the same for '68. I have a 302 aircleaner on my 289 coupe and I can not tell the difference, but there might be a slight size difference.
Doug

So if its to big will it be a noticable diff in size I.E. wobble? Or will it just not seal tight? to big meaning 4V AC on a 2V Carb. ???

No it will not wobble...and I looked at my Mustang build guide and they show the 289 and 302 aircleaner as being identical (except for the heat riser tube which will not effect how it sits on the carb). I will still send you a pic of the correct one when I get home.
Doug

Brandon,
Here is the pic of the 68 aircleaner, the only difference is the opening at the end of the snorkle, the 302 has a larger opening (this is the 302 aircleaner I have on my 289). The other part in the pic is the heat-riser. I hope this helps
Doug

Yeah mine looks identical to that one!

Personally I like the 289 HiPo air cleaner (which is what I have on my GT/CS) but if your going for the original one I don't know.

The L shaped part, what is it and where does it hook up to? DOes the hole under the Snorkle attach to anything either?

Brandon,
it is the heat riser, it attaches to the exhaust manifolds. It is used to aid in cold weather running. The two holes you see in the heat riser attach to studs in the exhaust manifold and the round opening fits into the opening in the snorkle. The flapper in the snorkle would open and pull warm air from the manifold during cold starts and running. I will attach a pic of it on the engine. I hope this helps.
Doug

Where are the headers then? and 289's had heat risers?

Brandon,
The 289 did not have "headers" they had exhaust manifolds (though some same they are the same thing), the heat riser attaches to these. I attached a pic of the exhaust manifolds. The heat riser will not fit if you use non-factory manifolds/headers.
All Mustang engines, 302, 390, and 428's had heat risers unless they had the chrome dress up aircleaners on them.
Doug

Ok thanks for clearing that up Doug =)