Have you ever wondered why your truck diesel is a straight six?

Ford started putting the V8 internationals in pickups in 83, but they were in farm tractors before that and Iirc some single axle trucks too.

 

Here's the $120000 car that Volkswagen made that most people have never seen.
There's a guy that lives near me that drives one of these.

 

Already replaced it. And yes it was expensive.

 

V-8 Cummings and Macks also Detroit 318 and two hooked together for v-16.

 

To answer the OP's original question, the inline 6 yields more torque than other configurations of equal displacement and is considered more perfect in that respect.

Engines that are V's or flat/opposing will rev higher and quicker because of the piston/rod angle in relation to the crank.
Instead of the piston moving straight up and down like an inline engine, they move at an angle to the crank which reduces the downward force of gravity on the piston tops and rods.

I can't say for sure, but I think that's what Chrysler had in mind when they built the slant six.

 

I'll take a properly tuned Mack E9 V8 any day. Or a new Scania V8 that was derived from the old Mack.

Nothing sounds as nice as a straight piped E9.