2nd upper arm mount/Instant Center

N_F_S

N_F_S

Active Member
Hello all, regarding the 2nd upper arm mount, with a “bolt in” Ford 9” if you don’t raise the housing upper arm brackets 2” can you lower the upper arm at the front mount with the anti squat brackets? Is there enough clearance with an aftermarket straight arm or a home made straight arm, or do you have to use an aftermarket banana arm?

I’m thinking, due to the 9” pinion offset; (to the driver’s side) the 2nd upper arm brackets are very close to the pumpkin housing, (basically right on the shoulder) - not raising the upper arm brackets on the housing, the aftermarket arm might hit the housing when lowering the upper arm at the frame using the anti squat brackets.

Any thoughts?


Thanks,
J
 
Toms63SSQB

Toms63SSQB

Well Known Member
Supporting Member 8
I have the drop in ford 9" rear end in my 62 Impala and the upper control arm bracket is actually welded right to the pumpkin, It is about 1/3 on and 2/3 off. There has been a lot written on this subect you might want to start with this link. I am sure there will be more members responding to your question. I used UMI adjustable upper control arms and used the stock location on the frame to mount.

http://www.348-409.com/forum/showthread.php?t=15302&highlight=upper+control

good luck,
 
Fathead Racing

Fathead Racing

Well Known Member
Supporting Member 7
Ok, I'll bite. Lowering the control arm at the frame mount will decrease the clearance between the arm and the housing. Raising the mount at the housing will increase the clearance. You right about the housing mount being close to the pumpkin, in fact one side of the bracket is welded to the pumpkin. Raising the bracket at the housing may allow you to use a straight arm.
 
N_F_S

N_F_S

Active Member
Thanks for the replies,

I'm working on my car now after 15+ years of sitting in the garage. I'm most likely going the 9" route.
I was just wondering if I don’t raise the mounts, will the arm hit the pumpkin housing, or will I have to use a banana style arm.

J


Anyone ever use a Dana 60?
 
Tic's60

Tic's60

Well Known Member
Supporting Member 3
fatride said:
Ok, I'll bite. Lowering the control arm at the frame mount will decrease the clearance between the arm and the housing. Raising the mount at the housing will increase the clearance. You right about the housing mount being close to the pumpkin, in fact one side of the bracket is welded to the pumpkin. Raising the bracket at the housing may allow you to use a straight arm.
Click to expand...

I run the raised mounts with straight adjustable arms I built :D Mount is 1/3 on and 2/3 off the pumpkin. There's pics on here somewhere.
 
N_F_S

N_F_S

Active Member
So, running a 9" I can use a 1 piece driveshaft and I do not have to cut the driveshaft tunnel.
Correct???
 
CDNpontiac409guy

CDNpontiac409guy

Banned
Actually, with a 9 inch, due to it's somewhat shorter length pinion, the driveshaft ends up being even longer, which is even more of a concern when using a 1-piece driveshaft. With a factory, unmodified X in the frame, you would have to watch your suspension travel.
The first thing you'll encounter though, is what is known as driveshaft "critical speed"... the by-product of driveshaft diameter / length / RPM.
Remember, driveshaft RPM, in high gear, is equal to engine RPM, and with an OD trans, it's that much faster.
Stout gears in the rear end ( 3.70's or more ), make this more of a concern.

There are a few threads here in the forum, which talk about "critical speed".
 
cheap1

cheap1

 
Supporting Member 1
N_F_S said:
So, running a 9" I can use a 1 piece driveshaft and I do not have to cut the driveshaft tunnel.
Correct???
Click to expand...

I'm running a moser 9" in the Biscayne with a one piece driveshaft. So to answer your question yes you can. Some of the issues I ran into with this combo are that my ride height was higher than stock, that combined with the lower pinion on the 9", and the one piece driveshaft created some problems. I couldn't get enough negative pinion angle for the car to hook up and not wheel hop. I had to cut part of the tunnel out and lower the car 1 1/2 " to correct the problem, but everything is good now.
 
N_F_S

N_F_S

Active Member
Well it sounds like I will have to cut the bottom of the tunnel.

I plan on drag racing the ol'gal, I've been working on the cage and soon Ill be working the underneath areas of interest.
I don’t intend to have the back of the car higher than stock ride height (at least right now anyways) I just want to know what I should look out for.

"Driveshaft critical speed" is another issue that I have to look at too.
 
09Jud

09Jud

Well Known Member
Supporting Member 2
I installed a 1 piece drive shaft in my 61 and had to notch the plate on the bottom of the chassis . I am running a Danna 60 with CE ladder bar suspension . I choose the Danna because it is stronger than the 9 inch even if you weld 20 pounds of gusites to the ford rear to reinforce it . 9 inch rears have a lower pinion that eats more horse power and make you notch the bottom plate even more. I welded my drop loop cross member to the frame and to the rocker panels reinforcing the frame . my opinion is that you do your car similar to what I did. I use to work in a chassis shop. For me so far this has been working well and is much stronger than the stock suspension. I think you will have a lot of problems trying to use the stock type ,even if you use stronger control arms and you go as fast as you hope to you will tare the brackets off the frame. Good luck with your project and I hope I was able to help.
 
N_F_S

N_F_S

Active Member
09Jud,

Did you tub the car? I am not tubbing the car, this is going to be a street/strip car.

So the Dana 60 fits back there, are you running the stock gas tank?
Are you using any type of reinforcement inspection cover?
 
09Jud

09Jud

Well Known Member
Supporting Member 2
N_F_S said:
09Jud,

Did you tub the car? I am not tubbing the car, this is going to be a street/strip car.

So the Dana 60 fits back there, are you running the stock gas tank?
Are you using any type of reinforcement inspection cover?
Click to expand...

My car has stock wheel wells,gas tank and is stock bodied except for the rear suspension. I believe my Danna was from a roadrunner . till now I have not needed a reinforcement cover but I think is cheap insurance. I thought I had pictures of my rear suspension but cant find them. Im still looking.
 
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