Can't give you '48-specific info, but:

Yes, the long main board holddown bolts have to be into the crossmembers, and therefore (in your case) have to go thru the wood crossmember too. This is what holds the bed onto the frame.

Yes, the interior bedstrip bolts do go thru the crossmembers (where the two match up). Because of the wood under the main floor on yours, I suspect your DC bedstrip bolts may be too short, although mine (for '52) were way long (maybe they use the longer '48-50 bolts for all, to simplify stocking?). In any event, if yours are no good for your application, I'm sure you could sell them.
Good luck, looks nice!

-- Ross

 

I had the wood in the bed of my 50 , as the floors were steel from 1931-1950, they had a hardwood sub floor. The wood count for the 48 is 6 pieces with 5 metal strips.
The sides as you mentioned are different from the 51-52, as they have a lip for the outside boards to go under. On the 48 right near the fender location there is a little bit of a rise, and the strips will not hold the boards down. They will warp and look like hell.
If I was to do it again I would tack a piece of angle on each of the bed-sides, and as you mentioned dado the outside boards, enough for them to fit under snugly. The strips that go between the boards will both hold down the wood and the bed. There are 6 special bolts and washers, I believe that hold the bed to the chassis. Also there is an end cap that holds the boards to the rear, so you won't get slivers, and whatever else.
If you and should get the stripd pre-drilled, as they are stamped for carriage bolts, and you will have to do a bit of light drilling, to get the carriage bolts between the wood.
Its been a long time since I done a 48-50 floor, but if done right its is well worth the effort.
I got my kit from Mack Products in Moberly, MO. here is their web address, hope this will help you out. There are others that sell there products, best of luck to you.

http://www.mackhils.com/mack_products/
.

 

5 Star, it sounds like you don't have two layers of wood as F1Fordguy does? Otherwise I wouldn't think you'd have the problem with the slight rise at the fenders.

Just to clarify my earlier response, the long bed holddown bolts go thru the steel and wood crossmembers and the frame. That is what holds the crossmember to the frame.

 

Yes sir your right, I guess I didn't read where it said it was a long bed. Just to clarify it my 50 had the short box with a hardwood sub floor, that is what the steel floor was supported by.
When I took the steel floor out, and put the wood in I left the sub floor intact, and the oak planks over that.

 

I will check and see if the lip on the crossmember is wide enough to catch a 1/4" carriage bolt. It is currently under the wood cross member piece and I guess I will have to drill holes thru the wood and metal crossmember. You can see the lip in this pic:



I don't think the bolts I have will be long enough. If I went thru the wood and centered in the cross member I would need at least a 5" carriage bolt!

What a PITA!!

Tim

 

You asked about the angled trim for the bedside. I found mine at Sacramento Vintage Ford, advertised as correct for '53-56. Matches the skid strips perfectly and is 1" high x 1 1/2" wide. You can go to my gallery for a look at this on a 48 box. (link should work)

https://www.ford-trucks.com/user_gal...=80153&width=0

 

mtflat
Did you hit the cross member with all of the strip bolts? Also you obviously put a wood riser on the cross members--did you just hit the "lip" with the carriage bolt. Does your carriage bolt go thru the wood riser and into the lip.

Tim