By chance are you selling FHP and/or HGTC springs or replacement springs for the 575? I have a standard 575 but would love to tighten up the suspension a bit.
Clyde, I am in the process of switching from FHP springs to HGTC springs. The reason is simply that I ended up with so many HGTC pieces on the car that in the interest of long term value it should all be HGTC. The FHP suspension made me very happy. In regards to the sale of the FHP springs, they are committed to another member. He is just waiting for me to deliver. You were second in line showing interest, and if the other individual changes his mind I will be sure to contact you.
Thanks again for your interest.
Also I believe Taz posted that FHP shocks and standard shocks are the same, just the springs, sway bar and ECU's were different.
Fabio, these rear springs are exact in every dimension. Only the part numbers are different. And yes metallurgy is the only explanation for any difference in stiffness. However my guess is that they are the same. The rated number on the FHP is 245#. Since published information is limited on the HGTC springs I took them over to a local NASCAR race shop here in Daytona Beach, FL. and had them tested. The rear HGTC's measured at 240#. Basically the same.
The front HGTC springs are 95% identical to published dimensions specs for FHP. However they tested out at 425#, where as if my memory holds the FHP's are rated at 400#. The race shop did pay a compliment after the test, saying that they were very high quality springs as their numbers were very consistent.
Fabio, if you ever have the opportunity to measure your factory HGTC springs front and rear, I would really enjoy knowing your wire diameters to compare.
Once finished changing these over I'll post a more detailed report and pictures comparing FHP and HGTC springs.