[leeklm]

When rebuilding the chasis, I installed Moog 5428 front springs, which tested about 40lbs more spring rate than the stock units. Problem is now the front end sits plenty high, about 1/2 to 3/4 inch higher than factory (after accounting for tire size).

I plan to call Moog to get an idea of the spring rates listed for their 590 springs compared to the 5428. Somewhat irritating that nobody seems to list the actual spring rates! What a concept...

For those that have replaced the front coils, what are you running? My car is the 73 Sport Coupe/GTO with manual steer, brakes, no a/c and no center console. Running factory style 4-core rad, iron heads, and aluminum intake.

Thx.

[1973ramairman]

Originally Posted by leeklm

When rebuilding the chasis, I installed Moog 5428 front springs, which tested about 40lbs more spring rate than the stock units. Problem is now the front end sits plenty high, about 1/2 to 3/4 inch higher than factory (after accounting for tire size).

I plan to call Moog to get an idea of the spring rates listed for their 590 springs compared to the 5428. Somewhat irritating that nobody seems to list the actual spring rates! What a concept...

For those that have replaced the front coils, what are you running? My car is the 73 Sport Coupe/GTO with manual steer, brakes, no a/c and no center console. Running factory style 4-core rad, iron heads, and aluminum intake.

Thx.

Yes I had the same issue with the springs. Sat way too high , I could not get a answer so I bought the springs from ames with handling package car sits fine . I think the MOOG'S are just a universal type of spring . My car is a 4 speed no a/c p/b and p/s bench seat , the car had the handling package code for front's was BP,according to the spring rate chart in the parts book I have. I know for sure 100 % the rear's are ZZ , when I took the car apart there was a red sticker stuck to the top of the spring with black letters . Saved it then had it reproduced.

[leeklm]

Found spring specifics on the Orielly Auto site, but goes against what a guy would think based on the Moog site. They list the 509 for a sport coupe with 5.7ltr, and the 5428 for a sport coupe with 6.6ltr. Based on these specs, the 509 would take me in the wrong direction... Of course never mind that a 5.7ltr and 6.6ltr would weigh the same.

Additional Details - #509
• Bar Diameter (In): 0.70 Inch
• Bar Diameter (mm): 17.9mm
• Bar Size (mm): 17.9mm
• End 1 Type: Square
• End 2 Type: Tangential
• Free Height (In): 16.350 Inch
• Free Height (mm): 415.3mm
• Inside Diameter (In): 4.08 Inch
• Inside Diameter (mm): 103.6mm
• Install Height (In): 10.50 Inch
• Install Height (mm): 266.7mm
• Installation Height (In): 10.50 Inch
• Installation Height (mm): 266.7mm
• Load (Lbs): 2374 Lbs.
• Spring Style: Constant Rate

Additional Details #5428
• Bar Diameter (In): 0.70 Inch
• Bar Diameter (mm): 17.9mm
• Bar Size (mm): 17.9mm
• End 1 Type: Square
• End 2 Type: Tangential
• Free Height (In): 16.830 Inch
• Free Height (mm): 427.5mm
• Inside Diameter (In): 4.04 Inch
• Inside Diameter (mm): 102.6mm
• Install Height (In): 11.50 Inch
• Install Height (mm): 292.1mm
• Installation Height (In): 11.50 Inch
• Installation Height (mm): 292.1mm
• Load (Lbs): 2078 Lbs.
• Spring Style: Constant Rate

After more research, they list the #5278 for a 6cyl car, which has an installed height of 10.5", about 1" lower than the #5428 I currently have. Spring rate is about the same.

Additional Details
• Bar Diameter (mm): 16.7mm
• Bar Size (mm): 16.7mm
• End 1 Type: Square
• End 2 Type: Tangential
• Free Height (In): 17.500 Inch
• Free Height (mm): 444.5mm
• Inside Diameter (In): 4.09 Inch
• Inside Diameter (mm): 103.9mm
• Install Height (In): 10.50 Inch
• Install Height (mm): 266.7mm
• Installation Height (In): 10.50 Inch
• Installation Height (mm): 266.7mm
• Load (Lbs): 2083 Lbs.
• Spring Style: Constant Rate