Modifying a semi truck

Modify how?

 

Modifying it in what way?

 

Is the truck a low roof or a mid roof, because some loading places don't have room for tall roof trucks to pull under chutes and go under and you will have to back out and can be a problem if trucks are pulled in behind you and you have to have them all back up to let you out from under chute??

 

Do you already own a truck?

 

For the money it'd cost to swap a transmission you'd be further ahead finding a truck with the powertrain you want already installed.

 

Then my advice to you is don't worry about modifying the truck with a fancy dash and bumper. Get it, run it for a year and see if you can make money. The first year is the roughest for a guy starting out and that money you spent on a dash might come in real handy when 3 tires blow on your third week.