Originally Posted by
Bob Parmenter
As Robert mentioned that's a real common area for the tin worm. It gets that way because of the way the original X member and it's rear extensions fit inside the outer rails and form a pocket of sorts in that area that holds debris then moisture.
Which brings some questions to mind on what's in the pictures but not in your commentary. It appears the X member was taken out, presumably to make room for the repair shown. Likewise, the corresponding portion of the X member that was inside of that rail rot suffered similarly? I'm not sure you need an inner plate or boxing if you intend to replicate/restore the original design which effectively acted as a doubler for the frame rail. I don't see where any tie bars were welded to the rails to maintain geometry when the X member was removed. I would hope you have some way of jigging the rails to return them to their proper position for frame integrity before final welding. The more welding you do without holding them rigidly in their proper orientation, the more twisted/bulged/disformed they will become. Not trying to rip on what you're doing, just throwing out questions/thoughts. You might want to rethink those short ladder bars too if you haven't already. The combination of short travel, and straight down the side rails with the spring being a center mount is going to be real bindy. Look at some of the commercially available rod frames with a transverse rear spring and notice how they typically have long bars or wishbones that pivot more toward the forward center of the chassis which gives the outer axle ends more ease of movement. Drag cars can get away with that short style, side mounted ladder bar because they're on a relatively flat road surface and are intended to function best only in a straight line. Road driving is another kettle of fish. The front wheels look to be too far back in that first picture, but then they're turned a might so it could just be the angle of the pic.
The cab size can start getting tight for a driver approaching 6 foot or more, though we're not all proportioned the same as far as leg length even when we're the same overall height. If that is an issue one trick is to make the seat back cushion thinner. With the variety of foam densities available today, a thin back rest that is still supportive is very doable. It's easy to gain a couple inches, perhaps more depending on you comfort needs, that way. And, if you're going to change up the steering column for a number of reasons you can tailor that angle/position for improvement as well.