Overkill or just badass

I've been looking at alot of rock crawlers lately. Mostly just for fun, but I would like to build one sometime in the future. Maybe start with my bronco. So, in doing totally a hypothetical bench build at this point, I have been wanting to upgrade my bronco to a full tilt rock crawler rig. Its a 1986 bone stock 302 v8 automotive. Fuel injection. I've got a 1970 351w on the stand for a future powerplant. I saw on craigslist this week a 2.5 ton Rockwell driveline driving front end for $800 and a Rockwell front steering 5 ton with the pulleys for $1000. Are these both way overkill or just badass. Obviously I would need a rear to match. Or do I just go Dana 60, 70 or 80 instead? Maybe ditch the bronco as a crawler, keep it a light wheeler and go full tube chassis truggy type crawler?