I have a 4 inch drop 40 ford axel, 32 frame built by SoCal, model A crossmember, all mounting hardware from SoCal Speed Shop. As you can see from the pic the distance from the axel to the spring is about 8 inches. This is more than I hoped for. I expected the frame to sit lower. Am I doing something wrong???
In "spring over" applications with a 37-48 Ford axle you need a special spring made by Posies. It will be the correct with for your perch spacing and also have a lot less arch. That said, I don't care for the 37-48 axle in spring over applications. The distance between the king pin and perch is narrow. This means your tires do not have room to make a full arc when turning. A better choice is the 28-31 Model A axle (2.25" perch boss) or the 32-36 axle (2" perch boss). The spring perches are closer together and this gives you more turning radius. Most aftermarket dropped axles have the narrower 28-36 perch width as well. My roadster has a SoCal frame. I used a CE dropped axle and spring. My current Model A project uses a dropped 35 axle and ultra-low Posies spring. Hope this helps!
You'll be ok. I see your shackles are straight out or up, when they are pointing down at 30% you'll be lower. Also try mounting your split bones inboard (under the frame) to gain room for the tire when turning. The later axle kingpin to perchpin distance is shorter. Keep taking pictures.And share them as you go along.
What the heck is that sticking out the bottom of the wishbone under the perch there? You should have a castellated tapered nut on the perch bolt that sockets into the tapered cup of the wishbone. Tighten to a fare-thee-well and install a cotter pin. That setup you have there is, I hope, temporary for setup only.
I used a '40 dropped axle front end on my '32, with a Posie's spring. I added 3 extra leaves to it, from the '40 spring, because it was going to have a LOT of extra weight on it (blown Hemi). I also used the "bent" '40 wishbones, and split them. The wheels turn all the way past where the bump stops would have been. I cuttrimmed the "spring forward" spring eoff and went to "spring over" perches. With no engine installed, it sat a little bit high, but with the engine in it sits right where it needs to be. With the '40 spring in, it sat WAY too high..
Are these factory-bent wishbones? I can see that the ends look like they've given you an extra couple of inches of clearance, but I thought it was only the spring perch section in front of the axle was bent from the factory? Looks good, by the way.
REM - I'm pretty sure they're Factory. I BELIEVE that the '40 axle was longer than preceeding years, and the bend was to give more steering clearance. Somebody jump in and correct me if I'm wrong...
The wishbone wasn't bent like that from the factory. I've seen this several times on older hot rods, and it was done after the wishbone was split to get back some turning radius (and for all the reasons being discussed on this thread). Whoever did yours looks to have done a nice job, so I can see how you might have assumed the wishbone left the factory like that. As for the original poster's question...it'll drop A LOT with the weight of the body, engine, trans, radiator etc...Don't get discouraged. It looks like you bought the correct Posies spring for the application, so it'll be fine.
Put your jack stands under the axle and the weight of the frame alone should take it down another inch, then expect it to go down about about another two inches once you've got the weight of the running gear and body on it.
For frame setup, P&J used to recommend using only the main leaf of the front or rear transverse springs. This "mockup" is close to where the frame will sit when the spring is complete and the frame loaded with engine trans radiator body etc.
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