620 leaf springs

[Anonymous Waffle]

I've been reading up on doing 720 leaf springs on a 620, and I read some info that different trucks had different # of leafs in a pack.

 

My long bed truck has 4 main leafs and a large overload leaf, similar to a 521's leaf pack.

 

Vs pictures I've seen of 2 main springs and a overload.

 

I'm aware my truck used to be a farm truck, could the p.o. possibly have changed out the springs, or are long bed 620's rated for more weight, thus having more leafs?

[datzenmike]

The '73 had  (standard cab short wheelbase

 

2 X 0.28" thick

1 X 0.24"

2 X 0.51" ....The '73 spring constant was 145 to 650 pounds per inch

 

 

The '78 KC had Standard cab long wheelbase

 

2 X 0.28"

1 X 0.51" .... the '78 spring constant is 106 to 308 lb/in.

 

 

Some 520s were rated to carry over a ton on their springs. Rather than change to lighter springs for a lighter payload on the later 521/620, they just kept them and lowered the rating on paper. This is just an opinion. At some point the springs were reduced for a better ride.

[red13]

I have d21 leafs on mine Apprently

[fastdadd]

720 4x4 springs will be lower than 620..d21 will go even lower but the center alignment pin are in different locations

 

i have 720 4x4 with the over loads from 620 put on top of the main leafs to flatten the even more i think i ended up with a three inch drop