Found a donor vehicle today, a 75 K20 suburban that I was hoping I could use the rear leaf springs with a ORD shackle flip for my 70 K5. Are these factory springs 56"? Can anyone shed some light on whether or not these will work? It also has the tranny and transfer case which I didn't check but I'm assuming it would be a th350/203. I will have to take a look on Monday. Thanks!