someone is making dropped axles for model t speedster that have more space between the king pin and spring perch. And you end up with wider tread space. My speedster I beam was dropped years ago and it narrowed the tread width. One of My roadsters used an old dirt car straight tube CAE axle. I just had to design the spring perch mount to get the ride height I wanted. If you look at the time and materials to build an accurate fixture, and then build axles it's hard to make the numbers come out right. at one time I was thinking about using 70's F 100 spindles, disc brakes etc and bosses to make a couple tube axles but found a couple old I beams , Lincoln brakes. buick fins etc .