At the track I'm running a bias-ply ET Street tire...

 

Well if you are looking for a semi-beefed up SRA, i have a 01 GT i just bought about 2 weeks ago that has 4.10's and had all bearings replaced. im looking for a IRS from a cobra...

 

Ha ha small world. Well what do you have with the solid axle? Do you have any of the brake lines, brackets, and do you have the stock gears? 3.55? Send a private message

 

PM Sent...

 

You dont need aftermarket controls arms, all you need is a SRA axle from 99-04, control arms from 99-04 sra, im pretty sure your brakes and stuff should swap over fine.

 

as far as rear springs goes for these chasis with a sra, stock springs cut 1 coil have been tried and true and recommended by some of the big names in mustang drag racing setups. Before you start hearing about cutting springs being ghetto, please remember these cars use linear springs which means cutting the springs wont effect the spring rate like it would on a progressive spring.

 

What is the difference between a linear and progressive spring?? and explain what you mean about cutting the springs?? Should i cut the stock ones off the gt or the irs?

 

This is from another site, but sums it up well, the reason to cut the linear springs is to get your desired ride highth, instead of buying a lowerspring which would be less ideal for drag racing than a factory spring. For the SRA you would use the GT springs.

1. Normal Springs (Linear rate Springs, Specific Rate Springs)
In a normal spring, space between the coils are equal. Normal (or linear rate) springs are designed to respond with a specific rate when compressed.

Consider we have a 10-coil spring, each coil spaced 2 centimeters apart. Put a load on the spring to compress it 2 centimeters. Because in Normal Springs coils compress at the same rate, this 2 centimeters will be divided into all 10 coils equal, resulting each coil spaced 1,8 cm apart. Put another additional load which is the same as the first one and the coils will become 1,6 cm apart.



2. Progressive Springs (Rising Rate Springs, Progressive Rate Springs, Progressive Wound Springs)
In progressive springs each coil is spaced differently and have a variable spring rate. When free, it is easy to compress progressive springs for first centimeters. As you apply more forces, coil on a progressive spring come closer. After a certain point, coil at the top 1/4 of progressive springs begin to touch each other and finally become inactive or dead, and that makes the spring stiffer. Apply more forces to a progressive spring then it becomes stiffer because as the number of active coils in a spring decreases, the spring rate increases. So, progressive springs may both be sensitive to very small bumps on the road, while giving the stiffness you need during hard braking and turning.

 

Just to reply to some questions the mach 1 sra was not 31 spline, it had 3.73 gears with MT drag radials 10.5 x17s. Now I have 31 spline mosers with eaton posi. Between that and the spec stage 3 clutch the torque that's put down is ridiculous. New springs are in order I might try finding gt springs and cutting them as stated above. These FMS b springs are the stiffest springs I've ever felt no weight transfer at all