Difference between F40 and F41 shocks

[Blake W.]

My '65 came with F40 shocks originally and I was wondering what, if any difference there is between F40 and F41's. I realize I'll probably never get a set but I am curious as to the differences. thanks in advance. Blake

[Joe L.]

Re: Difference between F40 and F41 shocks

My '65 came with F40 shocks originally and I was wondering what, if any difference there is between F40 and F41's. I realize I'll probably never get a set but I am curious as to the differences. thanks in advance. Blake

Blake------


There was no difference between 1963-65 F-40 shocks and the 66-69 F-41 shocks. They were exactly the same.

[Philip C.]

Re: Difference between F40 and F41 shocks

Blake------


There was no difference between 1963-65 F-40 shocks and the 66-69 F-41 shocks. They were exactly the same.

Joe I think the 69s and up were smaller in dia.(rears) do you know when they went from the month/ week date to day of the year. Thanks Phil 8063

[Joe L.]

Re: Difference between F40 and F41 shocks

Joe I think the 69s and up were smaller in dia.(rears) do you know when they went from the month/ week date to day of the year. Thanks Phil 8063

Phil------


I think the change to the slightly smaller diameter F-41 shocks did occur in 1969 but it was very late in the model year. I think that most 1969's with F-41 used the same shocks as earlier F-40 and F-41.

SERVICE changes imply a very late 1969 PRODUCTION change-over, too, allowing for a little time for SERVICE inventory of the older part numbers to be exhausted. The 1963-69 3171488 HD front shock was known in SERVICE as GM #3166559. That piece was discontinued in January, 1971 and replaced by GM #5559365. The latter shocks carried part number 4949806 on the shock and I believe these were the late 1969 HD front shocks which were of slightly smaller OD than the earlier 3171488.

GM #3166560 was the SERVICE part number for the GM #3171489 1963-69 rear HD shock. It was discontinued in April, 1970 and replaced by GM #4940459 which carried on-shock part number of GM #4940607. This was the late 1969+ HD rear shock of slightly smaller OD than earlier. Incidentally, the GM #4940459 was discontinued only fairly recently and carried the GM #4940607 on-shock part number right to the end. Its configuration did change slightly over the years, though.

I do not know when the change took place in the dating nomenclature of the F-41's. However, it may have occurred at the same time the smaller OD shocks came into use.

[Mark D.]

Re: Difference between F40 and F41 shocks

The earliest date I have seen on the 607 rear F41 is 006 69 so the change appears to be at the beginning of calendar year 1969. I have never seen a real 489 rear dated in calendar year 1969. I'm not saying they don't exist, I just have never put my eyes on one. I purchased an NOS set of 607 rears for my 69 dated 099 69.

Mark

[Jack H.]

Re: Difference between F40 and F41 shocks

There was no difference between 1963-65 F-40 shocks and the 66-69 F-41 shocks. They were exactly the same.

This is a real 'nit', but factory original shocks were date coded, so that's the answer in terms of what's different, eh?

[Dick W.]

Re: Difference between F40 and F41 shocks

There was no difference between 1963-65 F-40 shocks and the 66-69 F-41 shocks. They were exactly the same.

This is a real 'nit', but factory original shocks were date coded, so that's the answer in terms of what's different, eh?

Some people might get far enough under a car to judge the rear date codes, but it is all but impossible to read the fronts on a lift.