All things being equal such as condition and milage, the class eight will outlast the class 7. If paying more for a class eight and it is the same year, it would depend on the price differential.
If it was a tractor and then stretched after its trailer service, I would have it professionally inspected to ensure the modification was done to specs.
Will you get more loads? Much of that depends on the company and how they utilize their fleet. Keep in mind that it has to be enough to offset additional taxes, maintenance, tolls, and a drop in fuel economy verses a single axle. It may or may not be a benefit.
With regards to taxes, much depends on the state you are to register it in. It would be advisable to call your state IRP office for a exact quote. Additionally, some states require you to pay personal property tax on your vehicle. Amounts if any depend on the state you reside.
There are numerous posts here on EO dealing with your subject. Just go to the archives and perform a search.
Good luck
Davekc
owner
21 years
PantherII
EO moderator