what is the biggest motor i can put in my 05 chevy colorado?

[I love my wife and kids]

it has a 5 cylinder in it and is 2 wheel drive what is the best and easiest to do
and transmission

[stevie_d_55]

The biggest engine you can easily swap in with just wiring harness and mounts would be a 350 I would say. If you want to spend the money and don't mind major modifications you could go with 600 to 700 cubic inch engines but that would be a ton of work. I would go with a 350 with a turbo 350 tranny