1966 Corvette - F41 Suspension

[Richard M.]

Re: 1966 Corvette - F41 Suspension

Confidential Chevrolet production records indicate the following:
F-41
Special front & rear
Suspension Equipment
---------------------------
Exc. Units

AA 2,705
AB 0
TOTAL 2,705

This would indicate the option was only installed on one type engine equipped '66 Corvette

David, Does your RPO data show the ECLs AA and AB are engine specific? Are the RPO data listed ECLs NOT the same ECLs defined for build trim levels. Unless I'm totally misunderstanding the ECL translations......

Trim ECLs AA and AB are Coupe Trim code inclusions and exclusions for RPOs A31, A82, M35, and N03.

The 1967 RPO data for F41 is, in fact, engine specific.

AB L88 20
AC L71 2,178

.....which for the 1967 model year is clearly specific that NO 390Hp(L36) or 400HP(L68) cars had F41 suspension.

Rich

[Jack M.]

Re: 1966 Corvette - F41 Suspension

The 1966 Corvette Dealer Order sheet makes it quite clear that you could order an F41 suspension with a 390 or 425 hp car. Thanks to everyone who provided responses. I'm having a tough time getting a good printout of the dealer order form. Could whomever posted it please email me a copy direct. My email is "pete@leclairent.com". You could also text it to me at 970.396.6000. Thanks again,

Pete

Pete - That is the ONLY copy I have... nothing better. I will try to enlarge it, and send you an email (it may NOT be pretty).

[Jack M.]

Re: 1966 Corvette - F41 Suspension

Rich- I had a little difficulty with the figures from David (then again, I have difficulty with lotz of other thingz).
Looking at Noland's book (pg #342), I see the following:

F-41 Special Front and Rear Suspension
--------------------------------------
ECL . Usage ..... Units

AA .. With L72 .. 2,705
AB .. With L88 .. 0
TOTAL ............ 2,705

(NOTE: ECL AB was dropped on June 15, 1966)

[Wayne M.]

Re: 1966 Corvette - F41 Suspension

Here's a copy from Vette Vues Magazine reprint back in '90s. Form is revision 8-65.

[Joe L.]

Re: 1966 Corvette - F41 Suspension

Wayne------


This order form and the one posted by Jack are from the same dealer and the order numbers are only a few apart. So, the form posted by Jack must also have the 8/65 revision date. As I mentioned previously, my copy of the 1966 Chevrolet Order Guide is dated 11/65 and specifies that F-41 is only available with the 425 hp engine. So, it may be that the F-41 engine prerequisite was changed sometime between 8/65 and 11/65.

[Richard M.]

Re: 1966 Corvette - F41 Suspension

Rich- I had a little difficulty with the figures from David (then again, I have difficulty with lotz of other thingz).
Looking at Noland's book (pg #342), I see the following:

F-41 Special Front and Rear Suspension
--------------------------------------
ECL . Usage ..... Units

AA .. With L72 .. 2,705
AB .. With L88 .. 0
TOTAL ............ 2,705

(NOTE: ECL AB was dropped on June 15, 1966)

Jack,

Good reference research. That data in Noland's book is definitely in conflict with David's RPO data, as the official GM data that he has does not differentiate engine usage like it does for the 1967 data. I would imagine Noland had access to the same data that David has available. I have seen that identical data and have occasional access to it.

That is unless his 1966 data specifies ECLs AA and AB definitively as the engine usage.

I am 50/50 on my belief about this iisue. The Order sheet you shared is at least proof that somewhere in the GM data it shows F41 usage with L36 availability, but I would agree with Joe that the Order form may have been in error and the RPO could have been rejected by St Louis.

Yes if a "Authenticated" Window Sticker showing F41 tied to a L36 can be found, then this would help clarify(or confuse) the issue. I know of no such car but will be on the hunt from now on.

Pete, BTW, where Joe spoke of the F41 rear shock/strut mount uniqueness, this post has photos of replated originals on a 1967 L71/F41 car. Note the cast part numbers are identical on both, with the unusual 3829265-66 casting number on each. The casting numbers are unusual because after machining to make Left and Right parts, the only difference is visual. Finished part numbers 3829265 Left, 3829266 Right. Assembly line parts had the above features. I recal, but could be in error, that Service replacements used a ink stamped number identifier instead of the cast numbers.

Also shown are the non-F41 shock mounts for comparison, 3820929 LH, and 3820930 RH.

Rich

[Michael J.]

Re: 1966 Corvette - F41 Suspension

I have been following this thread with some interest, since my '66 has an L36. It does not have F41, which anecdotally was explained by the original owner, since he wanted every option possible on the car he ordered and checked all the boxes. The window sticker has 19 items, including things like C60, N03, J56, K66, P48, N32, N14, leather, etc. Because he wanted A/C, he said the dealer told him he could not have his preferred L72 engine, and the suspension that he had checked, so he took the L36. The car was ordered near Christmas, 1965. Not solid evidence at all, but that's the story.

[Joe L.]

Re: 1966 Corvette - F41 Suspension

... the Order form may have been in error and the RPO could have been rejected by St Louis.



P I recal, but could be in error, that Service replacements used a ink stamped number identifier instead of the cast numbers.


Rich

Rich-------


I think the order would have to have been rejected at the zone office level. I think if the order got to St. Louis the car would have been built with F-41 suspension. I think that St. Louis would have only rejected an order if there was a fundamental reason that a car could not be built with a specified option.

Original F-41 shock mount shafts had raised forging numbers. SERVICE units did, too (I have quite a few NOS examples that do [none for sale]). However, in later SERVICE the forging dies apparently changed and the forging numbers were omitted.

[Jack M.]

Re: 1966 Corvette - F41 Suspension

As a followup, I located another early '66 Dealer Order Form... it was from an Al Grenning article in the Spring 2001 Restorer. The quality is much worse that the one JohnZ sent me, so it is somewhat difficult to read. The order number (top/right) is lower that the image posted previously, so it also lists the 390HP engine as a possibility for the F41 suspension (though we know that subsequently changed).

I may be reading this inkorrectly, but the earlier picture had 37-G-1 (Zone 37 - February - Production Sequence #1) in the bottom/right... and this image has 11-G-110 (Zone 11 - February - Production Sequence #110). The first one was mailed to St Louis on 1-13-66, and this image indicates a mailing date of 1-31-66.

[Pete L.]

Re: 1966 Corvette - F41 Suspension

Jack,

This is getting good. Thank you so much for handing in there with me on this issue. I only wish that someone would come forward with a window sticker showing L36 (390 hp) and F41.

Thanks again,

Pete

[Henry J.]

Re: 1966 Corvette - F41 Suspension

I have a General Motors Products of Canada Limited document entitled "Dealers' Confidential Price Bulletin", for the 1966 Corvette, that I received from Vintage Vehicle Services in Oshawa when I enquired some years ago about my own car. This document is dated October 7, 1965.

Listed under F41 is the following description: "SPECIAL PURPOSE FRONT & REAR SUSPENSION: Includes special springs, matching shock absorbers and special front & rear stabilizer bars (avail. only when 425-hp engine is ordered)".

[Jack M.]

Re: 1966 Corvette - F41 Suspension

Michael - That sounds like an AMAZING '66 you own... wonderful background history, too.

Pete- I'm not sure 'hanging' is a word I'd like to hear... as a fan of Western movies, I fear I may be on the wrong end of the rope.
As mentioned, there are very little 'pros', and a boatload of 'cons'... with so few F41's made, and much fewer window stickers remaining, itz the proverbial 'needle in a haystack' search. Then again, I have no clue why you would even hide a needle there. Best of luck on your quest!

[Pete L.]

Re: 1966 Corvette - F41 Suspension

Thanks for that information Henry. Since the Dealer Corvette Order Forms, that are provided earlier in this thread are dated March, 1966, and they show that you could order an F41 with a 390 HP motor, I'm hoping that GM made the F41 available to 390 HP cars a little later in the model year than October 7, 1965.

Thanks,

Pete

[Paul C.]

Re: 1966 Corvette - F41 Suspension

1966 Passenger Car and Truck Price & Facts Books, First, Second and Third editions for 1966 all have the identical description:

[Jack M.]

Re: 1966 Corvette - F41 Suspension

I'm bringing this thread back with some updated/expanded info... and I seek your help with ongoing research.

On various forums, the availability of 1966 Corvette options F41 & J56 have been discussed many times.
In the latest 1966 TIM&JG, F41 is noted with 'Judging Guidance' as ONLY available with L72 engines...
Whereas, option J56 is listed only with Big Block engines (meaning BOTH L36 and L72).

Updating some of the documentation I've collected, we see the following details:

These excerpts come from an EARLY 1966 Corvette Dealer Order Form (the form has a print date of 5-65).
The person was initially ordering an L36 engine, along with special suspension and heavy duty brakes.
Note that the 427 engine horsepower was originally listed as 400 HP (L36) and 450 HP (L72)...
And you'll notice that the suspension option code was initially listed as F40 (similar to previous years).
This L36 Corvette Coupe order was placed at Ripley Chevrolet (Ohio), with a hand written order date of 9-15-65.
The order form was REJECTED/RETURNED by the Cincinnati Regional Office (with hand written notations).
1966 Corvette Order Form - Dated 5-65 (F40 & J56 Ordered 9-15-65).jpg


The back side of the form was STAMPED in Cincinnati on Sep 16, 1965... and again on Sep 30, 1965 (after all changes).
The Corvette was eventually built approximately November 11, 1965 (VIN 54XX).
1966 Corvette Order Form - Cincinnati Stamps.jpg


Looking at a sample order form (dated 8-65), the option code is now F41, and engine horsepower has been reduced...
But the F41 & J56 options are still being listed as available with BOTH the 390 and 425 HP engines.
1966 Corvette Order Form - Dated 8-65 (F41 & J56).jpg


The initial 1966 'Finger-Tip Facts' dealer album had F41 ONLY with the L72, but J56 with BOTH L36 & L72 engines.
1966 Finger-Tip Facts (F41 & J56).jpg


Viewing Corvette options dated 11-1-65, 2-15-66 and 3-16-66, F41 & J56 are now listed ONLY for the 425 HP engine.
1966 Corvette Order Form - Dated 11-65, 2-66 & 3-66 (F41 & J56).jpg


Using the dates on order forms, is it possible that F41 & J56 were initially available on BOTH the L36 & L72 engines?
We know that 1966 Corvette production started approximately September 1, 1965...
Early order forms (even one dated August 1965) still had F41 & J56 available with the L36 engine.
But the 9-15-65 order (placed above for an L36 & F40/J56) was rejected in Cincinnati on Sept 16, 1965.
Obviously, there were many deviations in the Chevrolet paperwork (Henry & Paul's docs date to Oct 1965)...
And we have no idea how accurate the 'print dating' was on these documents.

So was there a window of opportunity for any of these options to be included with the L36 engine...
Did the availability of these options somehow change/fluctuate during the model year...
Could dealers easily obtain an override on some of the options?
Many questions... especially since some members appear to have legit options.

If you have a 1966 Corvette with F41 and/or J56, please chime in with your specific info:
- VIN & Build Date (partial VIN is OK)
- Engine option (L36, L72 or ???)
- F41 and/or J56
- Any paperwork/info to confirm the options (images are nice, but not necessary)

If you have any other 1966 Corvette documents/info that address these issues, I'd also like to hear from you.
For those with privacy concerns, you can contact me CONFIDENTIALLY via forum email or PM.