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I have gotten conflicting answers on what my coil springs actually fit. My car is a 66. The front coils I have measure 16 1/4". Some have told me they may be for a 68 or above others and some on Ebay that supposed to come off of a big block mid year are saying they are 16 1/2". I need to know if my springs are correct for a big block without A/C Mid year corvette. Second question......If you have big block coils in the front what spings should be in the rear or is there a difference. I know there is a 7 leaf and 9 leaf. Was the 7 & 9 leaf rears an option or really something to it?
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Re: Coil Springs Again, Please Help!
There seems to be a lot of controversy about springs, and I've made some notes from past posts I've seen. All I can contribute is info I've gathered from those notes and my own reading:
In Noland Adams' Vol 2, page 450, there is a chart with only two 1966 front springs specified:
The standard supension spring: 12 coils, 15.4 inch free ht, 5.19 outside dia, and 0.59375 rod dia. My '76 parts book seems to indicate this spring was also used for 427 cars (where F41 was not ordered) UNTIL very late 1966, when 427 cars apparently got their own springs (see 3888250/51 below). The 9-leaf rear spring is the standard spring.
For cars with optional F41 suspension: 10.84 inches free height with 7 coils, 5.15 inch outside diameter, and rod diameter of 0.6875 inches. This spring was originally #3832518, since replaced in service by a similar '74-'79 spring #340519. The 7-leaf rear spring is used for F41 suspension.
In 1967 (possibly late 1966) a 427 spring is included with a 14.26 inch free height, no other unique specs are shown)
According to a past post by Joe Lucia, late 1966 and all 1967 got additional springs for a 427 with and without AC. He says #3888250 was used for non-AC, with a free height of 17 inches (note: Adams chart says 427 spring height was 14.26 inches) and a rod diameter of 0.5625 (which falls closer to the F40 spring than the standard)... these specs were taken from separate posts, so may not be accurate; spring #3888251 was used for AC 427's (no dimensions given).
At least one post I've seen claims all 427 cars used the 7-leaf rear spring, but Adams' book says the F41 suspension was intended to be an option with L-72 (400/425 hp 427ci) engines only, and that approximately half of them came that way, indicating that the standard suspension actually WAS standard on big-block cars through most of the 1966 model year.
Noland's chart says the standard suspension 427's got 0.875 front torsion bar, as opposed to 0.75 standard and 0.9375 for F41.
Confusing, ain't it? -
Re: Coil Springs Again, Please Help!
The AMA specs in the restoration package that you can receive complementary from GM Customer Service should have enough data on the springs (free length, wire diameter, number of coils) to positively determine if you have the proper OE springs.
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