The NV3550 is "conservatively" rated at 300 ft/lbs at a GVW of 7200 lbs. I dont think you can destroy it with a small block very easily. Our Broncos only weigh ~4500 lbs (much less w/o a hard top), so unless you tow a boat, have a big block and hit the nitrous, your probably OK. Maybe a 393 or 408 stroker with some aftermarket heads and nitrous would be enough to tax it...I am not an engineer. Its supposed to be a sporty shifting tranny too which I like. I guess its like everything with this disease, it all depends on what you plan to do with it. With a 4:1 1st gear, its deeper than a stock 3spd for the trail and the 0.78:1 OD will make for decent cruising speeds to get you to and from the trail or road-trip. Personally, I'd rather have a smoother, faster shifting unit than an industrial strength tranny, because its more fun to drive...4wd muscle car...but it sucks having to save the coin for one of them (hell, any of them for that matter). One day.