Original leafs?

[got2haul]

Anyone know what the original leaf spring configuration is for a 1/2 ton short box?  I presume 1973-1987s were all the same except the heavy halfs?  Mine has an RPO that says heavy duty rear springs, code 1G50; however I have 5 leafs with no overload spring.  (I suspect the overload spring was removed by a previous owner.)

[HAULIN IT]

I would agree with your assumption that the overload was removed.  Lorne

[VileZambonie]

yup all the rear ones cames with the +1 spring. But the # of leaves depends on the specific truck. Mine had 7 I just replaced them with 8+1 and took out the +1 and made it 8. It didn't effect the ride height

[Captkaos]

Generally speaking on the 73-80 (not 100% of the exact termination) the 53" = 3+1, THE 56" = 5+1.  The 81-87 were 53" = 5+1 and 56" = 7+1.  There were more scenarios though as Vile pointed out.

[VileZambonie]

My 1980 C-10 Custom Deluxe had 8+1 from the factory (originally Diesel Truck)

[got2haul]

The leaf spring length measurements you mention... how is the measurement determined?  For example, center of eye to center of eye in a straight line or center of eye to center of eye, following the arch of the spring, or some other way?  I'd like to measure mine to see what it is I actually have.  The truck has several 1981 parts on it (i.e. a motor from a 1981 GMC), so it could be that the springs are later model, too.

[Captkaos]

Eye to eye (relaxed).  53 is the standard spring, 56 is the HD spring.  The perch on the rear will be a lot closer to the rear of the frame.

[VileZambonie]

Mine have always been 56", never had 53". I thought all the shortbeds had the shorter spring no?

[Captkaos]

Short bed Heavy Half,  HD or Big Ten all had 56" springs on the LWB or SWB, same goes for the Long beds.

[VileZambonie]

Didn't know that... but now I do 

[joesgarage71]

 My 78 K-20 SWB has 53" springs in the rear. My friend has a 80 K-10 SWB and a 79 C-10 SWB with 56"springs.
 I broke a L/rear top and had a hard time finding a used one.