Ok I am currently in the process of doing the Open Element mod and I am wondering if it is really worth buying a 130.00 or more K&N X-Stream Air Flow Assembly as compared to a 30.00 one at autozone how much diff in hp are we talking. Or actually how much rear wheel hp is this mod supposed to give. Last question what size carb flange does a 89 Formula 305TBI have? Thanx for any help

 

IMO it ain't worth it, and the flange is the standard 4V carb size (IIRC 5 1/8")

 

Care to direct me in the way of the better choice I prefer a black finish no tacky chrome top or a breather top like the K&N is cool

 

As far as performance it might give you a small gain over the $30 one, but not really worth it, but it just looks so damn sweet! I'm planning on buying one just for the looks, lol. It might work a little better with a cowl hood too.

 

I think the k&n is nice, but with a stock hood, it's not gonna get too much air through the top. Most 14x3" open elements come pretty close to the hood.
I'm using the Moroso flatbottom air cleaner (14x3") part #65911 ,
about $40 from Summit, though it's chrome (you could always hit it with a scotch-brite and paint it)
I'm using a universal 14x3" k&n element in it.
Every type of cold-air air cleaner setup I've tried has been more restrictive than the moroso unit, though it's better to get cooler air, rather than the hot underhood air.

-Rich-