Looking to purchase first truck! HELP

[Dre912]

Hello to everyone!
I'm a newbie so please take it easy on me. A few months back I made the decision to go do what I always saw as my dream job and of course that's owner operator. in the past years I have held a few different positions mostly welding related but now I seek to pursue one of my dreams and that's to own a big rig trucking company.
the goal is to start out small and maybe end up with a few trucks and a custom truck for me of course but for now I'm looking for guidance and all the information that you guys can give and share with me so I make a great purchase for my first truck.

Guys I'm needing some advice my advisors that I have are very biased towards the 12-7 Detroit which is a great engine but the only downfall is getting a truck with that engine sometimes it means getting a truck with a million plus miles and I'm a newbie I do not want to be overwhelmed with breakdowns.

I will be honest that I love all big rigs nothing is too far-fetched for me but one of my favorites is the t660 by Kenworth and the Peterbilt 386 but as you know there are only a few of these trucks for sale with the caterpillar motor and the rest have the ISX or Paccar. My advisors has warned me over and over how bad the ISX motors are and how costly it is to repair so after reading on this forum it has enlightened me about the ISX motor I definitely do not want the paccar motor. On the table is also the W900 with a cat or Detroit.

I have found quite a few t660 and Peterbilt 386 with decent miles 500,000 to 600,000 Plus with the ISX motor for good prices. with all this being said what are your thoughts on the trucks that I have on the table to choose from for this new career Adventure