Hot Rods Can you guys school this newbie on proper setup of a coilover rear suspension - Model A coupe hotrod

I bought a Model A coupe hotrod. It's my first, as previous to this my cars have all been 60's and 70's muscle cars. I built all them, but I figured for my first traditional hot rod, better to buy one, then go on from there. I bought this car because I really liked the way it looked. It's a 1930 5 window coupe, fenderless, and it's set up to be very low. The car sits very low on a custom made Z'd frame, and it has no rake at all, it sits level front to rear. I wouldn't mind adding just a very small amount of rake to the car.

The rear differential is a Ford 8.8", with a pair of coilovers of unknown make. The coilovers are already mounted in the top of three lower mounting holes. The rear axle housing protrudes through cutouts in what was the original arched wheelwells. There's only about 2" of clearance between the top of the axle housings and the tops of the cutouts in the body. Because of this, the axle housing will occasionally hit the tops of the cutouts in the body.

To prevent this, I believe the previous owner/builder put very stiff springs in the rear, virtually eliminating the proper amount of travel needed for a decent ride and proper suspension performance. I don't have access to proper scales to weigh the car. I know that's the correct way to determine the correct spring rate for the rear of the car.

All that being said, here's my questions:

1- I'm thinking that adding just a bit of rake will not only (maybe) improve the appearance of the car, but also create a bit more clearance between the axle housing and opening in the body that the axle housing p***es through. Given that the present shocks are already mounted in the top hole of the lower mounts, would a longer shock be in order? How do I determine what length coilover shocks I'll need? Is this the proper way to accomplish what I am thinking of doing? Am I correct in my thinking on all this?

2- Given that I have no access to scales, can anyone take a shot in the dark, an educated guess so to speak, on what coilover spring rates are normally used on a Model A couple hot rod set up like this? It's fenderless, original Ford steel body, regular trunk, no hood, ZZ4 small block Chevy with 700r4 trans. Nothing unusual in the car as far as equipment, and it should weigh similarly as compared to the hundreds of other similar cars, whatever that typical weight might be.

3- Is there a brand of rear coilover shock I should look at, or avoid? (A bit off topic, but with a straight axle front end, what front shocks also offer good results?)

I guess all of the above will cover the basics. Sorry for the length of the post, and if any of you guys feel like wading in and offering up opinions, I'd certainly appreciate it. This relatively new guy thanks you.

 

this is the set up on my brother's model a pickup im not shure the brand but i can find out if you want

Sent from my LGLS740 using The H.A.M.B. mobile app

 

Actually i believe there speed master

Sent from my LGLS740 using The H.A.M.B. mobile app

 

PS allow yourself at least 3" compression to bump stops. Shocks work best when laid over at the top, minimises a lot off unnecessary lateral movement. Vertical for 400yds at a time

 

Mine are sitting around a 75 degree angle. Adjustable.
I think maybe the best for you is what you think is best. Just don't go cheap and buy ****.

 

Doug 520. im a newbie to ridding myself and like you bought a car and I’m slowly changing it. I see this post is from 2017.
have you figured out the right spring weight. I like you have no way to weigh the car.
My shocks sit straight up with no angle. right now I have QA-1 with 220# springs. I haven’t got the car on the road yet but I’m getting close.
im thinking the 220 springs are to stiff. Considering the car doesn’t really move when I stand on the rear frame and push down.
I really can use the help trying to find a close spring rate. That rides kinda stiff but not like a semi- truck.

 

try 110 springs first then adjust.

 

Try 180# or 200#. You can also change the angle as mentioned above.

 

Which is easier???......... Buying & replacing your existing coil overs or.......just change the upper mounts by several inches? Since I'm so tight 'I-squeak-when-I-walk' I would look into making new mounts.
6sally6

 

If it’s the mounts I’m thinking of, there isn’t much to gain putting a hole in them to raise them, and over the axle would be too high.
But along those lines, he could lower the upper mount for the same thing.

I agree with fabbing up something different, cost of new good coil overs is damned pricey.

Edit: Bit by the old post syndrome, see that the topic has been changed to spring rates.