I have a 1973 F250 converted to a 5.9 Cummins back in 1987. I have recently repaired 2 cracks in the cross member located under the motor mounts. I am sure that this issue was a direct result of the additional weight of the Cummins (about 500 lbs) What I need to know is what can I do to prevent this problem from happening again. Do I need to replace the springs on my front end? If so what specifically do I need to replace them. Is there another alternative? Would replacing my current shocks with spring assisted shocks work for me?
Any assistance with solving this problem, would certainly be gratefully accepted and sincerely appreciated.

 

Build a better crossmemeber and allow for frame flex. The stock clamshell two piece cross member is not strong especially when you cut the top of it to clear the Cummins.

 

On old jeeps we would grind and then weld the crack. The put plates cover the crack and weld those on. Never cracked again.

But on the jeep it was due to flexing for extreme off roads.

In this case as suggested, if you can take the cross member off, just make a new one of thick and perhaps wider dimensions.