C2 and C3 F41 suspension vs. C3 FE7

[Mark #28455]

I thought the F41 springs were the same as those used for the FE7 Gymkhana suspension of later C3's.

The original F41 springs had 8 turns, but I recently saw a late 1970's original gymkhana car and the springs only had 7 turns. Does anybody know if there was a design change and when it occurred? Are the springs interchangeable or do the 7 turn springs make the front end sit lower like the aftermarket springs do?

Thanks,
Mark

[Joe L.]

Re: C2 and C3 F41 suspension vs. C3 FE7

Mark-----

The GM #3832518 coil spring was used for HD suspension applications during the 1963 through 1973 period. During this period, the HD suspension codes were F-40 (63-65) and F-41 (66-73).

For the 74-82 period, the HD suspension code was changed to FE-7. Also, the coil springs used for FE-7 during this period changed from those used for F-40/41 earlier. Several different springs were used for FE-7 cars over this period depending upon year and, in some cases, vehicle weight. These springs included the following GM part numbers:

340519
354131
362150
362151
14021601
14021602

[Mark #28455]

Thanks, Joe! *NM*

[Tom R.]

Re: C2 and C3 F41 suspension vs. C3 FE7

As a footnote to Joe's comment re the number of springs for FE7 from 74-82...I've observed FE7 with coil spring tags (part number and broadcast code) on a 74, 78 and 81. As Corvette put weight on in the mid 70's...spring weights were adjusted upward to accommodate the weight. So, a 340519 (spring weight=under 741) heavy duty spring in 74...became a base coil spring in later years. In 78, 362150 and 362151 (spring weight=795-847 and over 847) became the FE7 coil spring. By 1981, the 14021601 (and 02) became the FE7 spring with a spring weight of under 812 and over 812.

You'll recall by 1980, Corvette was put on a diet and greater use of aluminum alloys were introduced especially in the rear end differential, crossmember, etc. The 79 was the heaviest Corvette ever! So we see this adjustment in terms of the lower rated spring weights in the 80-82 FE7 options.

[Mark #28455]

any idea what the spring rates or free heights wer *NM*

[Jim T.]

Re: any idea what the spring rates or free heights

Mark not real sure what the spring rate was for the 3832518 spring. Think it is 550. I measured my set of 518 springs I bought from GM and used in my 70 for several years for height today. From the cut end of the spring end to end mine measured mine and they were just over 12 1/4 inches. When I installed them in my 70 coupe with air,power steering, power brakes, and 350 engine the car sat about the same as it did before I removed the original springs which I replaced because a couple of coils were touching with the car parked. I really liked the performance of the 518 springs.