retro-air cleaner?

This may sound like a dumb question but... Is there any way to change the current W115 300D air cleaner over to the other ( like on my 123) style air cleaner? The way I see it is this, if I get that big 'ol trash can looking thing out from that front corner and put an air filter on top of the engine I will have enough room to install a second tank under the hood in place of the "air can".

I should be able to get about a 6-7 gallon tank up in that corner pretty easily. ( this would keep my lines much shorter with less exposure to the elements and less chance of the oil cooling before it gets to my pump) Shorter lines decreases likelyhood of problems! Tom