MGKelly

I've read all the F41 posts and think this just might be a waste of time.
I bought a 68 L71 several years ago as a resto project. Don't have the tank sticker, invoice, but the body trim tag is still there.
So far all the numbers i've checked match either VIN or date code including engine, frame, carbs, trans, axle, everything is correct.
I have the car completely disassembled and surprised i didn't notice it earlier but the rear leaf has 7 springs. the measurements of the front/rear sway and larger shocks are correct for the F41 package.

is there anyway i can verify this package came with the car without the invoice?

Thanks for any help, J

MelWff

even if all the parts are correct, anybody could have installed them after the car left the factory at any time that they were available over the parts counter..

MGKelly

Thanks! That's what i thought. We'll maybe it will add some value.

J,

blue427

I thought f-41 was mandatory on an L-71. So if you know it's an L-71 than it's standard on that vette.There was a charge for it of course.

jb78L-82

Give the man a cigar^^^^^^^^^^^^^!!!!!!!!


All 427 V8 had the heavier front and rear springs, front AND a rear sway bars (BB's only):

Everything you want to know about what came with any Corvette can be found here: THIS SHOULD BE A STICKY so folks can look up many of the questions that constantly come up on the forum:

​​​​​​https://www.gmheritagecenter.com/doc...t-Corvette.pdf

MGKelly

Thanks for the help! I would love to agree as it would make my day, but I can't find the info in the pdf that supports F41 being standard in all 427's.
Didn't see it in the suspension or options section, do you know what page it's on? I thought the F41 option was only standard on the L88/L89 in 1968.

thanks again, J

ed427vette

And you will NOT find it either because that is not the case.

The F41 package was NOT mandatory for the L71 but was only an OPTION for the L71 only. I believe it was a mandatory option on the L88. They made a total of 1661 cars with the F41 in 1969. They made a total of 2722 L71's. Obviously not every L71 got the F41.

All 427's received larger sway bars but that was NOT the F41 package. The F41 package consisted of different shocks and 7 leaf spring.

You could not order the F41 with any other engine except the L71 and had to have it with the L88.

MGKelly

I'm sure the same still applies but we're talking 68 not 69?

jb78L-82

I am certainly not an expert on the 68 C3's but the later C3's, I am much more familiar with the option codes but looking through the Gmheritage center documentation for the 68 C3, one thing is apparent. The F-41 option is mentioned once on the option page for the 68 C3 and no where else throughout the 135 page document. This omission is odd since the later gmheritage center documents for other C3's do mention the heavy duty suspension differences versus the standard suspensions in the documentation.

In researching this question, I did note that the 427 L-88 definitely had a F41 suspension versus the standard BB cars as mandatory. Is it possible that the only 68 cars with F-41 were L88's...just asking?

A few things are apparent though. All BB 68's came with heavier front springs than the SBC. All BB cars had a 15/16 inch front sway bar versus the SB 68's 3/4 inch front bar. All BB cars had a 9/16 rear sway bar versus no rear sway bar for the SBC cars. All BB C3's received a 9 leaf rear transverse spring (the SBC 68's as well) but a different spring rate. There is no mention of a 7 leaf spring offered for a 68 C3 in the documentation which does NOT mean it was not offered, just not mentioned. There is no mention in the documentation of differeing springs for the BB versus SB cars..the same shocks are mentioned.

If there is an F41 suspension option for non L88 cars, the difference appears to be the 7 leaf heavier spring rate transverse spring and possibly a heavier shock...that is it. FWIW-Going to a much heavier rear spring without upping the front spring rate using the same stock sway bars would allow for much more oversteer so I would have to assume the F41 option also upped the front coil spring rates as well to go with the higher spring rate 7 leaf transverse spring.

Does anyone have strong documented evidence of the F41 components in 68/69 etc? Thanks

jb78L-82

I found this from a post 15 years ago:

​​​​​​For the 1969 model year, the following parts were included in the Corvette F-41 suspension:

15/16" front sway bar (standard bar was 7/8") - #3831972
9/16" rear sway bar (same as other 1969 big blocks) - #?

550 lb/in rate front coil springs - #3832518 (broadcast code "EA")
152 lb/in (per side) rear leaf spring (seven leaf) - #3828811 (broadcast code "EB")

Special shock mounts (provided clearance for larger diameter shock absorbers) - #3829265 (left) and #3829266 (right)

Special shock absorbers (physically, the fronts looked similar to standard equipment parts; rear shocks used a larger diameter shaft with a "coolie hat" instead of the standard equipment sleeve) - Afraid that I don't have the part numbers handy, but I can get them if you absolutely need them.

My understanding is that only L-71/L-89/L-88/ZL-1 cars could be equipped with F-41 in 1969... If someone has real documentation to the contrary, I'd really be curious to see it.

ed427vette

ed427vette

That is correct from everything I remember reading over the years. The only thing I would add is the F41 was not mandatory except possibly on the L88. This is for both 68 and 69. I quoted 69 production number above but the 68 are 1758 F41 cars out of 2989 L71's, 624 L89's and 80 L88's.

On both 68 and 69 dealer order forms the F41 option box states "for the L71 only".

MGKelly

jb78L-82

If you are not married to originality and really want to improve the ride, steering response and handling of your BB C3 you may want to consider some of what is on my 78 L-82 Gymkhana suspended C3.

Keep the 550 front coils-Same as on my SBC L-82 in 1978
Source a later front F41/gymkhana sway bar 1 1/8 inch
Keep the rear 9/16 rear OEM bar or go larger to a 3/4 inch OEM type sway bar...NOT an aftermarket style rear bar
360lbs or 420 lbs composite rear transverse spring
Bilstein Shocks Heavy Duties in front/Bilstein Sports in the rear with the 360 or 420 composite
Competition Heim jointed Strut rods

Your BB 68 with the above ^^^^^will handily outhandle, steer, and ride over any F41 BB C3...guaranteed

MGKelly

3X2

A little off topic but I remember something called a Daytona rear spring. What was different between this spring and a F41 rear spring?

MelWff

5 leaf spring, here is more info
https://www.corvetteforum.com/forums...ar-spring.html

MGKelly

The rear shock mounts are correct F41, they were not added they came with car. I know, no one cares but me, lol