Roper, be very careful thinking you can pull more than you should with a smaller vehicle.
It might get the job done for a while, but the repairs and safety issues will catch up to you.
There is nothing worse than having an underpowered Jeep, Suburban, Bronco whatever pull out in traffic pulling a horsetrailer.
They are not always built heavy enough to cope with the sway a trailer gives.
For example a 26 foot holliday trailer weighs about 3000 pounds give or take, but a 20 foot stock trailer weighs 4000 or more empty. Put 6 cows in that and it can real heavy real fast. And those cows aren't bolted down.
There is an old saying there is no replacement for displacement. That refers to it still takes a big engine to develop big power.
Semis were built with some 10 litre engines and the dealers said they would pull like a 14 litre... I have never seen a 10 litre used much on b trains. Since then the hp of the engines has increased not decreased.
The 6.5 in the chevy is a decent engine if you know the tricks. Number 1 throw away the plastic lid on the engine. I have 300,000 K on 2 trucks with the original injectors and pumps... I think I am starting to have small pump issues with the electronic one.
Poor fuel and heat are the real curse of any diesel engine... the 6.5 was just ran by too many "but it started why can't it pull" type of guys.
I love the guys that swear they will never pull with anything but a dodge or a ford, these guys get new trucks every 2-3 years. I haven't seen anyone I know keep a puller more than 3 years but my chev has been here for almost 9 and it was 5 years old when I bought it.
I will buy a brand new 6.5 after seeing the wrecks the dodges were at that auction...a 91 brought $2400 ...it was junked. There is a newly designed block selling complete $4800 US new heads, new everything...gear driven timing... so many upgrades the old 6.5 needed.
That a a cooling system upgrade I will have a like new old truck.