Depends what type of Freightliner engine. He could have a hx40 if its a baby Freightliner (8. 3) or it could be a HX50,HX55,HX60,or bigger. I have an HX55 that I plan to use as my second turbo on my twin turbo set up, but I wouldn't dream of using this in place of my HX35. By itself it would probably take 3 months to spool up.
Garry.