I have an older restoration '32 Tudor sedan that is completely stock except for a hydraulic brake conversion, that I think was poorly executed (but that's a conversation for another time). I'd like to put a 4" drop I-beam in it while retaining the the OE wishbone & steering. I've been trying to find information about whether this is even possible and I'm coming up empty. Is this even possible? It appears I have to use an axle that takes '37-'48 spindles, which is fine but the steering arms that would work are a big mystery. Has anyone done it this way? I gotta believe this has been done many times.
It’s been done a million times, and the best way is to use modified Henry Ford parts. Drop the stock axle or a 33-36 axle and it will be a direct fit in the wishbone. Grab some 37-41 or 42-48 spindles with their same year kingpins and they will fit the old axle. Heat and bend the steering arms before you install the new kingpin bushings. Lots of descriptions and videos on the spindle arm bending to study up on the process.
Son did it on the 32 Tudor which is LHD that we brought in from the US. He used a 4" dropped heavy axle and as I don't think he would have had the LHD later spindles he must have used the OG 32 parts. I can ask him tonight and get the details.
Installing a dropped Axle does not require splitting the bones. The most common reason for that is a Motor Swap that needs more Oil Pan space. You can buy bolt on dropped steering arms or Bill-Jerone. Don't forget to take Ackerman into consideration when messing with the arms. It's not Rocket Science, High School kids have been doing this since the 50's.
I have a pair of deep drop steering arms I just got from Roadster Supply that are made expressly for a 4 inch dropped axle with a deuce wishbone. The tie rod is under the bones and clears by about 1/4 inch. I needed them because my daily driver deuce pickup had the tie rod between the top of the bones and the frame and was constantly hitting the frame. Ray made them just for what you are doing.
A little off of the topic of your post but save this for another time. Here is the way I set up the hydraulic master cylinder on my AVATAR: Charlie Stephens