Pickup box bolt-up problem

[jon75]

When I purchased my 1975 GMC, the box had been swapped years before with a 1986 Chevrolet box. My issue is that the second set of bolts from the front do not line up with my frame holes. There are holes there but they seem to conflict with the front upper mount for the leaf springs.

With the leaf springs, exhaust, and driveshaft in there, it's kind of hard to get my head up in there to see what the clearance looks like. I am not sure if the bolts are different length in this location or not.

Between the two forward bolt holes in the bed are a set of bosses where they may have made holes in the old beds. The frame directly below these bosses have holes that look like they used to have bolts in them. So I am thinking that this is where the old bed bolted down, but I'm not sure.

I would like to know if all of this information is true...

If it is, what would you guys recommend I do? I can either drill out the forward holes (but that would leave the holes behind it exposed) or I can try and figure out how to get some bolts in the existing holes. Let me know what you think.

(sorry I don't have any pictures to show you)

[ray_mcavoy]

Yes, on 8' beds there were two different locations for that 2nd set of bolts back from the front.

Some are 14-3/4" back from the front and use bolts that are the same length as the other 6 bolts.

Others are 28-5/8" back from the front and use considerably longer bolts (about 10-1/2" long) that pass all the way through to the bottom of the frame. The location of these bolts lines up with the forward leaf spring hangers and crossmember.

From what I've seen, some trucks (particularly 4x4's) have some extra reinforcements on the spring hangers that would interfere with bolts in the 28-5/8" location so they use the 14-3/4" location instead.

So if your truck's frame has those spring hanger reinforcements, you'll have to drill some new holes in the bed floor to put bolts at the 14-3/4" location and put some plugs in the unused holes or weld them up.

[jon75]

After spending a couple of hours underneath the truck, I found that the spring brackets have the holes drilled for the opening in the '86 box. I think what I will do is add the correct holes in the frame so I can correctly add the bolt in the '86 location instead of the '75 location. If I get to a point where I am able to get the bed off, I can simply weld closed the holes for the '75 box. Sound like a plan?

[Truck Guy99]

DO NOT fill in the spot on the frame unles you live with a lot of salt. I have a pickup bed trailer from a square and found out he hhard way AFTER I bought another bed for it that they arent all the same. I wouldn't worry about it if it's only those 2 bots. If it bothers you that much, get the right bed. I have replaced a bed and it isn't too bad. Just be careful. I woul just drill the new hole in the frame and leave it be. If you are near a lot of salt, throw some paint on the old and new holes to keep the rust monster at bay. And remember, pics or it never happened.

[jon75]

I said that I would fill the extra hole in on the frame if I am doing the restoration. I guess I wasn't clear on this part, but I will probably do that with most of the unused holes in the frame. There are a lot of them! It's really not a big deal to me, and I'm not going to worry about it in case the next guy that owns it turns it into a trailer. That will be his problem, not mine.

[Truck Guy99]

Whatever floats your root beer...