Straight axle

[mechanixman]

Hello all,
I have a decision to make; and I want to know your guy's opinion before I do anything serious. The picture below is what I found my brakes to look like. I don't want to buy new cylinders at $70 a side. My solution there is get a cylinder off of a newer 70's pickup which brand new, costs $13 a side. But I would need to drill new holes in each back plate just to mount them.
BUT
I was cruisin and perusin craigslist, and found this set up:
http://chicago.craigslist.org/sox/pts/3771652867.html
And it'd be great if it weren't for the fact it's a 57 1/2 axle, and I have a 52 1 ton frame. So my question is: Is it possible to swap this one in for mine?
Either just to the kingpins or the whole axle.

Thanks