Rear Cross Sill help!

[connorsquarebody]

Hello, I’ve been searching the internet for DAYS trying to find bed cross sills + the rear main for my 1980 Fleetside Longbed. All I can find are for stepside beds or 1972 and below. Are other years/bed configurations the same size and I can use something from a different truck to complete this? Can’t move forward on project until this gets done and I’ve had no luck, what I’ve found is sold out. Thank you so much for any help.

 

[BadHabit]

Was looking thru AMD's catalog and noticed they offer the rear cross sill;

Rear Tail Pan / Cross Rail Assembly - Complete - 73-86 Chevy GMC C/K Fleetside Pickup; 87-91 Chevy GMC R/V Fleetside Pickup; w/ Steel Bed Floor Cross Sills | Triplus 900-4073-1

Complete rear tail pan / cross rail assembly for 73-86 Chevy GMC C/K Fleetside Pickup & 87-91 Chevy GMC R/V Fleetside Pickup. Correct for use on models with a steel bed floor only. This is rear most cross sill under tailgate. Stamped from high quality hea

www.autometaldirect.com

Near as I can tell, all other cross sills are not available thru them...only offered as an integral part of their complete steel floor assembly;

Bed Floor Assembly - Stock Tubs - 73-87 Chevy GMC C/K Short Bed Fleetside Pickup Bed Floor Assembly | AMD 790-4073-6S

Reproduction bed floor assembly for the 1973-87 Chevrolet / GMC C/K Squarebody Short Bed Fleetside model trucks

www.autometaldirect.com

Perhaps the older-year cross sills are offered because you could get a wooden bed long-bed fleetside back in the day?

 

[BadHabit]

If all else fails, try googling "hat channel". Its an industrial building product.
Might get lucky if what you need is a standard hat channel dimension.
16ga. mild steel would probably work nicely.

Hat channel + square tube stack a possibility too.

 

[etc86]

@BadHabit the cross sills from LMC etc are 14g I’m pretty sure. You don’t happen to have a measurement for the height between chassis and bed floor by any chance do you? I’m looking at the exact same problem but I live in Australia so freight isn’t worthwhile over just making something.