Projects Need help with a 1954 GMC longbed bed

My son and I are working on getting his '54 GMC longbed up and running, but need some help on the bed. When we bought the truck, the bed was held down with a couple bolts, but I cannot figure out how many "cross sills" and "cross sill supports" I need for the bed. I have found stuff for a shortbed, however, cannot find anything definitive on longbeds. Any help will be greatly appreciated!

 

Is it a long 1/2 ton or 3/4 ton ? Both used 8' boxes but there's some differences in the 2.

 

It's a 1/2 ton.

 

...should use the same crossmembers as a 1/2 ton, I'd guess 3 of em,..as short beds have 2 removeable x-members to hold wood....those beds are all the same in width..

 

Maybe LMC?Also classic industries.

 

Thanks for every ones responses so far. I've looked at Brothers, LMC, etc., but still can't find a for sure number on how many cross sills I need? Even in the shop manual and parts manual, I couldn't find a specific amount.
I appreciate your help...the HAMB rules!

 

I have one out back with no box - I'll count the mount holes & PM you ...

 

Thanks!

 

I'm thinking that on the back half of a 1/2 ton GMC long bed the only difference is the 9-1/4 inches added into the length of the frame and the extra middle crossmember in front of the regular middle crossmember.

This is the GMC frame that is going under my 48 Chev so I can stretch the cab and keep the stock length short box. I'll probably have to tweak with the front bed mount holes in the frame though.