F - 41 SUSPENSION INSTALLATION GUIDE
By Leigh Scott
One of the new options released for the 1966 Chevrolet Model Year was the F-41 special purpose suspension. Available on any
Full Size Chevrolet equipped with either the 396 or 427 Turbo-Jet Engine, RPO F-41 consisted of a rear sway bar, a large front
sway bar (exactly the same as the standard front sway bar on the station wagon), and higher rate springs and shock absorbers
also 14x6 JK Wheels, RPO P-12 (the same as the standard wheel on the station wagon) and 8.25 x14 tires were required options,
but not in-cluded in the F-41 package. In 1966, 3,914 Full Size Chevys were factory equipped with F-41, less than 1% of total
production!! Even though F-41 was only offered on big block cars, any 65 or 66 Full Size Chevy can be equipped with the F-41
package. The only recommendation is that your car have the 4 link rear suspension, in other words, two control arms on top
of the rear axle (to the frame) and two on the bottom. Some Chevys only have one control arm on the top right (mostly six
cylinders and 283's). 4 links are recommended because the side forces exerted on the rear axle with the addition of the rear
sway bar. The last time I checked, the only part still available from G.M. for the F-41 was the rear bar itself. The special
spacers and reinforcement will have to be made. As for the attaching hardware, I've come up with some parts numbers available
from G.M.'s standard hardware catalog. These can be ordered from any G.M. Dealer. The original attaching bolts and nuts were
fine threaded 7/16-20 where as the ones available in the standard hardware catalog are course threaded, 7/16-14. This small
deviation shouldn't make any difference, but I thought I should mention in case you are a purist like me!! Below is a list
of parts required for the F-41, excluded from the list are the part numbers for the springs and shocks, the reason for this
is the large variety of part numbers because of the different combination available from Chevrolet based on weight and body
style. Take a look at a spring chart sometime, it will boggle ya! The parts marked with an asterisk are still available from
* 1.446221 Plain washer, 4 req.
* 2.94141867/16-14x4grade8bolt 2 req.
* 3. 9422299 7/16-14 locking nut, 4 -req.
* 4. 9425686 7/16-14x2 grade 8 bolt, 2 req.
5. 3888725 special spacer, 8 req. (need to make these)
6. 3888726 reinforcement, 2 req. (same as above)
7. 3888727 special spacer, 2 req. (same as above)
8. 3856396 rear tie rod, 1 req.
* 9. 394926 rear sway bar, 1 req.
* 10. 3868640 front sway bar, 1 req.
11. 3903084 front sway bar bushing, 2 req
12. 3870768 14 x 6 JK wheel, 5 req.
13. 8.25x14 tire or equivalent, 5 req.
The first step in installing your F-41 is the making of part numbers 3888725, 726, and 727. These, unfortunately are no
longer available from Chevrolet but can be easily reproduced. I've included sketches of each part with the necessary dimen-sions.
For the 3888725 spacer and the 3888726 reinforcement you can use plain flat cold rolled steel the correct thickness, and just
cut it to size. For the 3888727 spacer, 1/2 inch cast iron gas pipe cut to the correct length works fine. In fact, the original
ones I have from Chevrolet look like they were made from exactly the same stuff!! As you have already noticed, 3888725 is
shown as being both round and square. Chevrolet used both types, so it doesn't matter which one use. (The original ones I
have from Chevy are square). The next step is the drilling of the lower control arms. Please refer to the drilling diagram
shown in the assembly instructions. After you have completed drilling the lower control arms, you can install your rear bar
following the assembly diagram. Next, if your car has the rear tie rod with the large end at the axle (I'm talking about that
thin bar thats mounted at the left inside edge of the frame and runs down diagonally to the right rear of the axle) you must
replace it with part number 3856396. This bar has a smaller bushing at the axle to help eliminate rear end sway. Unfor-tunately,
this bar isn't available any-more, but was standard on any 65 or 66 wagon, or any 66 with the F-40 special suspension. So,
keep an eye on those junk yards for station wagons! I After the rear bars are installed, you can replace the smaller standard
front bar with the thicker station wagon style bar. You must use the larger mounting bushings, part number 3903084, because
the stan-dard bushings won't fit around the larger diameter bar. Again, these bushings are no longer available, but Moog makes
a replacement bushing (Moog number K-8258) that works just fine. The sway bar links at the ends of the bar, will work for
both bar types so nothing special is needed there. If your links are worn out though, they should be replaced. That's all
there is to it. If you're not trying to make your car original, just throw on a set of gas charged shocks and a set of your
favorite radial tires and you'll be amazed on how well your 65 or 66 Chevy handles. It won't be like an '88 Vette, but it's
a definite improvement!!!
Download this info from here.The text file is in Word format and the diagrams are GIF.If you need these in different formats,
let me know and I'll get them to you.
click here to download the text file
click here to download diagram1
click here to download diagram2