I guess it's a known issue that these trucks like to rot their frame behind the fuel tank. My truck also has a small crack on RH frame rail, between the cab and the bed. I've welded that at least once.

Left side is no brainer, I already have the material to fix that, but I was thinking to make both sides stronger.

I've thought about boxing the C-frame from under the cab all the way to rear spring front hanger.
But my concern is that I might create another weak spot somewhere else, as the frame is designed to flex, and every once in a while I do some off-roading.
Or maybe I just weld some flat stock to lower lip of the C.
To box or not to box?

 

If the frame is more rigid, then rough terrain will just tend more toward lifting a wheel, rather than twisting the frame. I could see circumstances where they wouldn't really be desirable... but, having your frame doing the pretzel thing probably ain't the best either. With good suspension articulation, seems like it'd be a non-issue.

 

I don't know but of course want pics of whatever you do!

 

This is something I'm going to tune, I really don't like how the rear rides empty. But we'll see how it turns out.
I have a flatbed on my truck, which also strenghtens the rear part of the frame, and I need to make couple of changes which probably make it even more rigid.

 

I sure will take pictures

 

I've always been very skeptical of Sulastic shackles but some people say they help. I don't know if they technically make a 2nd Gen application....and apparently I don't care enough to do a quick web search.

 

I did look up the Sulastic shackles. And boy they are expensive! $530 a set, and after shipping, taxes and customs, they add up to a grand! Though they look well built and sturdy, but still they have limited lifespan.

 

Interesting idea, but, I just don't see the cost/benefit ratio for those.......

 

Did some reading, and apprently they take out the harsness from the rear suspension. Still too expensive, but I found similar product from Alibaba for $60/piece. Welded part vs Sulastics cast part.

 

I'd opt for duel shocks than buy them. You still have the front mount so in theory it's only helping to eliminate 50% of the harshness. This thread reminds me of an episode of American Hot Rod. There was a Model A frame that I believe was one of the workers. Boyd told him to box the frame but he wanted to keep it all original. There was a big argument over it. Cracks start from fatigue (flexing) so keeping it from "flexing" should greatly reduce the chance of it cracking.