Smallblock 400 in it for now. looking to upgrade to a fuel injected 454 but havent found one for the right price yet. Tires are 18.4 wide each, so just over 6 feet of width in the back. And yes, I do get stuck, in fact I get stuck often. Just goes to show, bigger tires won't get you stuck less often, cuz you just find a deeper hole to try. it definately goes to show a 14 bolt can hold up to jst about anything, haven't had had a prob with it yet (other than blowing about 4 rear driveshafts, I am in the process of upgrading to a 2.5 ton mil driveshaft in the rear).