1975-80 Shock Absorbers

[Tom R.]

Three different shock absorbers set were offered between 75-80 and I'm curious to hear from L82 or FE7 owners with original shocks to confirm this. ECL codes would make this a lot easier. I'm not sure if the same packaging was offered year-to-year in that period but AIMs in the late years show this pattern.

A base set was delivered on L48 cars with auto tranny and non FE7 cars; fr-4984575 and rr-4984576.

A stepup HD set was equipped on L82 cars; L48 with FE7 and L48 with M20 but non FE7; fr-4984577; rr-4984578.

Than there are those Corvettes that ordered F51 heavy duty shocks and got fr-22012402 and rr-22025105.

The detail of shock information in the early years (up to 77) trail off from 78-82. Your insights and contributions appreciated.

[Joe L.]

Re: 1975-80 Shock Absorbers

Tom-----

As I've mentioned previously, shock absorber part numbers were "prolific" and "ever changing".

Basically, for the 75-82 period there were, FUNCTIONALLY, 2 different sets of shock absorbers. The "HD" shocks were used for some applications besides FE-7. In these applications, the "HD" shocks were combined with "standard" springs. For the most part, the applications that used the "HD" shocks with standard-rate "springs" were 1977-78 Corvettes with L-82, but there were some other L-48 applications that may have used them, too, in the 75+ period. The information on this is "sketchy" and I'm not even sure that it's accurate.

Beginning in 1979 through 1981, the "HD" shocks were available with "standard-rate" springs only through option RPO F-51. They were also, of course, used on any car ordered with FE-7 which also included higher rate springs.

The GM #4984575, front, and GM #4984576, rear, were "standard" PRODUCTION shocks used for "standard" suspension on most 76-79 Corvettes, except the exceptions as described above. The GM #4984577, front, and GM #4984578, rear, were the "HD" shocks used for the "HD" shock applications described above.

The GM #22025105, front, and GM #22012402, rear, were the PRODUCTION successors to the 4984577 and 4984578. They appeared during the 1979 model year. I believe that there were also PRODUCTION successors to the "standard" shocks which appeared in the late 1979 or 1980 model year, but I don't have the part numbers at the moment.

As far as I know, there were never 3 FUNCTIONALLY DIFFERENT sets of shocks that were used simultaneously for Corvettes in the 75+ period. There were the "standard" shocks of whatever part numbers and the "heavy duty" shocks of whatever part numbers. The "HD" shocks were used for some 75-78 L-48 (possibly), 1977-78 L-82, 1979-81 F-51, and ALL 75-82 FE-7. The "standard" shocks were used for everything EXCEPT the foregoing.

[Tom R.]

Re: 1975-80 Shock Absorbers

That makes sense on the basis of my field observations...meaning f-4984577; r-4984578 were superceded by GM# 22025105-front, and GM #22012402-rear. So if this true, then when 79-81 FE7 was ordered an owner got the 5105 and 2402 shocks or if the owner ordered F51 they got the same part number. They probably couldn't order both because all they would get is an extra set in the box.

I've got a picture of an 80/81 FE7 rear shock with the last four digits reading 2402...I didn't think when I was under to get my mirror and look behind the shock to get the full number but this was a low-mileage corvette in Bowtie judging and eventually awarded four stars.

I also know my 78 AIM calls for the 4984577 and 4984578 shocks for HD applications other than non L48 applications as we've described.

This also indicates the FE7 had two sets of HD shocks during its lifespan. From 75-78 the 4984577 and 4984578 and than from 79-81 the 2402 and 5105 series. Of course as you have indicated...there may have been another before 78...the 75-77 NCRS tech manual indicates the broadcast codes for a heavy duty shock in 75 but no part number.

Anyway...appreciate your patience and time taken to research. Let me know if come across additional information that helps to crystalize usage.