First time dropped I-beam axle install...advice?

Decided to go dropped I-beam on the '46 Chevy p/u. I've researched as much as I can,but I want to be insured that it handles properly,is set up properly,and is safely designed.
I dig the t bucket style mounting, a simple shackle clamp centered on a spreader bar. I want that altered wheelbase and in the weeds look. One question, with the frame level front to rear, do I want the spring mount perch level? I know of the 5-7 degree ideal castor at the kingpin...but wasn't sure if to prevent binding, if the mount should reflect that tilt as well.
From the top of the spring to the hub centers, what is a typical vertical height? Trying to figure ride height to get an idea. The frame horns on the Chevy have the typical turndown. I was looking at placing the spreader tube in the channel, running it forward until it pinched out, then box everything from there back. I wasn't sure if the drop in the frame horns would result in a noticeable ride height difference. I'm not running fenders and it's a rat, so altering axle placement isn't a big deal, nor is motor mount or cab mount. I can easily slide everything back to mate the cross tube on a flat frame section if needed. I really like the axle out front with rearward suicide springs.
Anything else to consider ??? Would like to hear from experienced old school guys that have played with this set up before. Thanks!!!

The spring perch mounting pad is level with the frame. All that has the caster is the axle.
I used 3" heavy wall tubing for the spring perch mounting bar.
It doesn't slide forward into the frame horn turn downs.
Typically you have a 1.5 to 2" settle in the ride height, when the engine and cab are mounted.
This is a spring behind the axle mounting.
This is my 33 frame. It has a 4" ride height.

Your frame should ideally rest on the wheels/tires and loaded suspension at a slight forward rake, usually around 2 degrees. You really need these pieces when properly setting up a chassis.

Old Iron said:

The spring perch mounting pad is level with the frame. All that has the caster is the axle.

Click to expand...

Not always true! It depends on the setup, which is why I said you need your pieces BEFORE building. Don't put the cart in front of the horse. If you are running hairpins with batwings and a spring-behind setup (like the pictures above), then yes you can make the perch level.

However, if you are running a spring over style then you will need either adjustable spring perches or to set the perch mount at the proper angle. Everyone has their opinion, but personally I don't think 5-7 degrees is anywhere near enough caster for modern speeds. I set mine at 10-12 degrees and they track straight as an arrow well into triple digit speeds on bias ply tires with no push in the corners. Proves it to me...

Thanks guys. This is exactly the info in looking for. I've bought the center shackle mount and a piece of 3" as a spreader. So if I set my frame at a two degree rake, as a default and place this center perch, I should be in the ball park? With the 4 bar set up I then can fine tune for 5-7-10degree castor?
4 inch ride height is enough to clear a pan using a SBC?
Looks exactly like the look in after. Let's keep going...

I do prefer the spring behind the axle style, FYI.
I see some where the tie rods are out front, and some are out back.
Do the particular kits dictate this option? I would like to run the tiny Vega streering box and this set up involves 'cross steer'??? Am I correct in my thinking?

Starting here:

I set the frame up at a 3 degree, then placed the spring perch pad 2 degrees reclined...this will give me somewhere to start.
I figure I'll end up in the 7-8 degree range, but could easily adjust it at the rear axle when fabricating that end.
No one can really give me a measurement to use from spring perch bottom to ford spindle center on a 4" drop/Low reverse eye spring.
I want to make sure Im not too low up front.
I guess I'll spend some coin, and mock it up. Z the frame if I have too.

At the Goodguys Puyallup show I looked at every straight axle Deuce that was there. I saw everything from 2-3° caster all the way up to 11°. Everyone will tell you their way is the best, but remember than not everyone drives their car very much or actually tries different caster angles or different setups in general.

I'm going to set mine somewhere around 5-7° when I build it, and then try some different setups to see what works best. Everyone has a different idea on caster angle and spring mount angle as well. I don't think it's the end of the world to have some twist in your spring, but if you can reduce it as much as possible that's probably best. I wouldn't lose sleep over it, though. So-Cal also sells these adjustable perches if you would rather take the twist out of your spring.

From what I know from talking to guys who have set up and drove with different caster angles and researching, going up to 11° or so makes it (slightly) harder to steer, and going down lower than 5° or so means it will be twitchy and won't return properly. I think the 7-8° you're aiming for sounds about right. Of course the whole system matters as well, the caster angle is only a part of it.