[99 to Life]

well keep in mind the original trucks rear wheels didn't line up centered in the fenders. reason being, when it had a full load it would squat down and be centered. So I would say the wheelbase needs to be a total of 128" on the original truck, but it is not. So if you use a 122" s-10 you can cut your box and possibly running boards to compensate to get the fenders to center up in the wheel wells. Or another thought could be move the fenders up a little on the bed and cut your running boards. Not sure if it would be noticeable or not having all the extra space past the back of the fenders. One thing is for sure. Not many guys use the longbeds, I personally would go for it.

Also I wouldn't think there would be any problems with the ext cab as long as it is 2x4