1967 F-41 rear leaf spring

[Dave C.]

I have was cruising around on the internet, looking for clues about 1967 435 horse cars, and one thing that I had never heard was that only L-71, and L-88 cars could be ordered with F-41 suspension, which included a 7 leaf spring in the rear , as apposed to a 9 leaf spring for standard suspension, the car I just bought does have a 7 leaf spring, which appears original. I have ordered every piece of literature available on the site, and I pick the car up on Wednesday, just wondered what you guy had to say about the F-41 option?

thanks

dave

[Richard M.]

Re: 1967 F-41 rear leaf spring

Dave, in '64/'65 F40 HD suspension could be ordered on any engine combination. In '66, IIRC, named changed to F41. Again on any engine combination. Applies to '67 also. Stock SB front sway bar was 3/4" .

If SB, F41 included a 7/8" swaybar up front and the 7 leaf rear spring and HD shocks. The BB L71 used a 15/16" diameter sway bar up front, along with the 7 leaf rear, and the standard BB rear sway bar.

On a note of interest, the 1967 AIM states all L36 & L71(edit also implies L68) had F41 as a required RPO, but it is in error. You could get a L36, L71, L68 without F41, but the front sway bar was 7/8", not 3/4" like the SB cars.......IIRC.

Rich

[Duke W.]

Re: 1967 F-41 rear leaf spring

The front bar on all F40/41 is 15/16" diameter; all base suspension big blocks, 7/8".

My understanding is that F41 was only available with L-72/71/88.

A lot of C2s have seven-leaf rear springs - many more than the number of F40/41 options installed at St. Louis. One reason appears to be that the seven-leaf was available from GM service parts long after the nine-leaf was discontinued.

Other F-41 characteristics are the front springs, all shocks, and the lower rear shock/strut mounts.

Duke

[Kenneth B.]

Re: 1967 F-41 rear leaf spring

The front bar on all F40/41 is 15/16" diameter; all base suspension big blocks, 7/8".My understanding is that F41 was only available with L-72/71/88.A lot of C2s have seven-leaf rear springs - many more than the number of F40/41 options installed at St. Louis. One reason appears to be that the seven-leaf was available from GM service parts long after the nine-leaf was discontinued.Other F-41 characteristics are the front springs, all shocks, and the lower rear shock/strut mounts.Duke

Now I know why so many C-2'S I looked at had 7 leaf springs in the day.

[Richard M.]

Re: 1967 F-41 rear leaf spring

Duke, Yes, I just went to the GMHeritagenceter.com site and the 1967 Vehicle Info kit pdf file says.....


F41-1.jpgF41-2.jpg

F41 special front & rear sway bars for 435HP. So front is 15/16", but what's the rear? I thought all rear sway bars were the same on all BB's.

In the AMA specs at the end of the document, page 2, it talks only about the .562" rear sway bar.

F41-3.jpg
F41-4.jpg

Rich
p.s. I think the front coils springs for F41 are 7 coils but I can't find that in the pdf.

[Wayne M.]

Re: 1967 F-41 rear leaf spring

F41 special front & rear sway bars for 435HP. So front is 15/16", but what's the rear? I thought all rear sway bars were the same on all BB's.

Yes; all rear big block C2 sway bars ('65 F40 or '66-7 F41) were the same, regular suspension or not. ( 9/16" dia. (=.562")

p.s. I think the front coils springs for F41 are 7 coils but I can't find that in the pdf.

F40/41 front springs #3832518 have 9 complete coils.

[Tim G.]

Re: 1967 F-41 rear leaf spring

I have never seen a documented 1967 Corvette 300, 350, 390, or 400 horse with F41.

[Gary B.]

Re: 1967 F-41 rear leaf spring

All,

When Joe Lucia and I wrote an article for the Restorer 6 or 7 years ago on the C2/C3 HD rear spring, we stated for '67 the following F41 ordering requirements:

Ordering requirements: L-71 or L-88 (note 1)
Number of '67s with the HD spring: 2,198

note 1: Although Chevrolet ordering requirements specified that F-41 was available with these engines only, a small number of cars with other engines MAY have been originally equipped with F-41.

For the life of me I can't remember the basis for that note, which applied to '67, '68, and '69. I hope Joe can remember and that he chimes in.

Gary

[Joe L.]

Re: 1967 F-41 rear leaf spring

Duke, Yes, I just went to the GMHeritagenceter.com site and the 1967 Vehicle Info kit pdf file says.....


[ATTACH=CONFIG]52412[/ATTACH][ATTACH=CONFIG]52413[/ATTACH]

F41 special front & rear sway bars for 435HP. So front is 15/16", but what's the rear? I thought all rear sway bars were the same on all BB's.

In the AMA specs at the end of the document, page 2, it talks only about the .562" rear sway bar.

[ATTACH=CONFIG]52414[/ATTACH]
[ATTACH=CONFIG]52415[/ATTACH]

Rich
p.s. I think the front coils springs for F41 are 7 coils but I can't find that in the pdf.

Rich------


The rear stabilizer bar was NOT part of F-40 or F-41; it was part of the big block option. All big block rear bars were 9/16" although three different bars were used over the 1965-74 period.

[Joe L.]

Re: 1967 F-41 rear leaf spring

All,

When Joe Lucia and I wrote an article for the Restorer 6 or 7 years ago on the C2/C3 HD rear spring, we stated for '67 the following F41 ordering requirements:

Ordering requirements: L-71 or L-88 (note 1)
Number of '67s with the HD spring: 2,198

note 1: Although Chevrolet ordering requirements specified that F-41 was available with these engines only, a small number of cars with other engines MAY have been originally equipped with F-41.

For the life of me I can't remember the basis for that note, which applied to '67, '68, and '69. I hope Joe can remember and that he chimes in.

Gary

Gary-----


I expect the basis for that statement is the fact that I was made aware of several apparently original, non L-72 or L-71 cars that were equipped with F-41 (as I recall, these were mostly L-36). Personally, I would be highly suspicious of any such car but I can't rule out the possibility. As far as published GM information was concerned, including those instructions on the actual 1966 and 1967 Corvette order forms, F-41 was available only with L-72, L-71, and L-88.

[John H.]

Re: 1967 F-41 rear leaf spring

Dave, in '64/'65 F40 HD suspension could be ordered on any engine combination. In '66, IIRC, named changed to F41. Again on any engine combination. Applies to '67 also. Stock SB front sway bar was 3/4" .

If SB, F41 included a 7/8" swaybar up front and the 7 leaf rear spring and HD shocks. The BB L71 used a 15/16" diameter sway bar up front, along with the 7 leaf rear, and the standard BB rear sway bar.

Rich -

The ECL codes tell the story on availability of F40/41:

1964 - Only available with L84 (and has no rear sway bar)

1965 - Only available with L84 or L78 (and has no rear sway bar with L84)

1966 - Only available with L72

1967 - Only available with L71/L89/L88

[Richard M.]

Re: 1967 F-41 rear leaf spring

Thanks for clearing that up for me John. I checked out a '65 recently that I thought had F40, a L76 365hp w/C60. It had a 7 leaf rear spring but a 3/4" front sway bar. Now it makes sense why. The 7 leaf must have been changed from 9 leaf previously. So this car did not have F40. Now it's more clear to me. Could you describe which ECL codes apply to those with F40/F41?

Rich
p.s. Joe, thanks for that info. Makes sense that only the BB cars had the rear sway bar. I do recall the recent discussion about the 3 versions.

p.p.s. Still much to learn.

Rich -

The ECL codes tell the story on availability of F40/41:

1964 - Only available with L84 (and has no rear sway bar)

1965 - Only available with L84 or L78 (and has no rear sway bar with L84)

1966 - Only available with L72

1967 - Only available with L71/L89/L88

[Dave C.]

Re: 1967 F-41 rear leaf spring

Wow ,lots of response , so from what I've read , it sounds like all big blocks came with a 9/16" rear sway bar, only L-71, L-89, and L88s could order F-41, which had a 7 leaf rear spring, as well as a 15/16" front sway bar, as well as nine coil front springs. I pick my car up tomorrow, I will check these things out.

[Duke W.]

Re: 1967 F-41 rear leaf spring

Now I know why so many C-2'S I looked at had 7 leaf springs in the day.

It may also have something to do with the way the ill-informed drool when they see "heavy duty".

The seven leaf spring just about doubles the wheel rate, so installing one with the base front springs and bar will signficantly increase rear roll stillness, which will bias an already dicey setup into even MORE tendency to oversteer, especially at the limit of adhesion.

Duke

[Tim G.]

Re: 1967 F-41 rear leaf spring

F41 rear shocks were different with a thicker rod and no dust cover on the top to cover the rod. I'm not sure of the dimensions, but it is thicker and exposed.