If you are going full width you should go with a d60 front from the start. The extra cost is not that significant in the overall price of building a rig. Run toyota RUF and f150s in the rear. This will save enough money to help offset the price of the 60 and and with the weight of the axles will work as well as anything you can buy. The only downside of a front 60 is you lose some clearance but since you are running a 70 rear this shouldn't be an issue. If you're looking to be a little narrower get a dodge front 60 instead of a Chevy. They are a couple of inches narrower and usually a couple hundred $ cheaper.