would this 73mm MAF KIT bolt up to an ebay CAI? or what? and would it actually gain an hp? what is the scoop.

 

No, that one will not, and even if you find one, it will not allow for more than 1 or so rwhp.

 

why is that?

 

It won't work because it does not have the little fin on the front which allows thefront part of the cai to mount onto the MAF. It's just an open tube (really made for 86-93 5.0L stangs) that has the air filter slip over it, and the heat shield over the air filter.

A larger diameter will not add more rwhp for one simple reason, your stock intake can only suck in so much air before it becomes full and can not suck in anymore, reguardless of inlet size. You'd need to port and polish the intake and heads, and do a cam swap to get more power with one of these, and even then the gain is small as hell.

Think of it like this, you have a 1" straw taped onto a 1/2" straw, and you suck in on the 1/2" side, no matter how large you make the 1" size, you'll still suck in the same amount of air/liquid with the 1/2" size until you make that size larger as well.