I don't know why everyone's gettin fussy about it
It has to do with the attitude you are putting out there. Kind of like a person who says I wouldn't own a Ford or Chevy, I'm a Dodge guy--They are the greatest. It is Bullshiite. You are welcome to have a preference but to make those kinds of statements is childish and ignorant.
There is NO such thing as the perfect engine. Many times one engine can be better than another, for a given application. Chances are though that there are many other engines just as capable of performing the same job and giving the same performance.
Some are easier to obtain, cheaper to buy, more economical to modify, capable of higher HP with fewer aftermarket parts. We are all looking to do something different, since the market as it is, doesn't offer what we want from the dealers. We all will also applaude going a step farther and going down a road less travelled. Trying to be different for the sake of being different and ending up with a poorer result though.........

Whoever has been blowing smoke up your *** about CATs being the end all be all of engines has done you a huge disservice. The fact that CAT has used Perkins as well as other engines and just slapped yellow paint and an emblem on them should prove that. Just as Cummins used Onans, GM uses Isuzu, Ford uses International and on and on and on the farther you delve. It has been done since the beginning, it just isn't always profitable for every company to make every size engine so the pick one that meets their durability standards and makes a contract. There are CATS, Deere, Yanmar, Scania, Detroit, Cummins, Isuzu, VW, Kubota, Deutz and countless other diesels that people hold as "The One". But its kind of like religion and all of it's Gods. Take your choice for the one that suits your needs and comfort, but you shouldn't try to belittle others because of their choice, it just shows a total narrow mindedness and lack of information.
If you want to do a CAT swap. More power to you. We will all help. We won't do all your footwork for you though. Do your own research and figure out which engine will fit your vehicle and intended end goals. Ensure you can get the parts you need to do the swap. Buy it and the vehicle and get going. Tell us about your project, show us your pics, etc. We won't decide on an engine for you-its not our money or effort being spent. We also won't do your research and hand it to you on a platter. As cool as the information age is you can generally find your own info in less time than it takes to type out a question and post it and the wait for one of us to read it and respond and then, ALL you'd be getting is one person's opinion--NOT FACTS you ferreted out on our own.