Engines for my hi-lux

To who ever reads this,
Hi my names is Daniel, and I have A 1986 hi-lux Dual cab. The engine in it is a bit old and small now ('86, 2 ltr) and it probly time to update. I was just wondering if anyone would know what other engines would fit as I don't want to go through the hassel of engineers reports but would like somthing with a little more torque and higher towing speed. I was hopeing to put in a later hi-lux engine, but don't want efi, or a computer that can fail in the bush. What would people suggest???