COPO F & SO number on Flint seat tag from 1969 Biscayne

[chadk]

I removed this seat tag from under the front seat of my Flint built '69 Biscayne. I was wondering if anyone could tell me what F4085 in boxes 12 and 13 means. It is a bare bones car that was ordered with L72 427, M21, 4.10 rear, and tinted glass. The original owner is still alive and doesn't remember ordering anything that would require a special order.

Thanks

[JoeC]

What is the rear end code? and gear ratio? is the code for 4:10?

in 1969 you can get RPO 4:10 gears but needed a COPO to get 4:56 or 4:88 for Camaro and Chevelle

For Nova you needed a COPO to get 4:10

Im not sure for Biscayne

you have to check the Power Team Chart

[JoeC]

I found a 1969 Power Team chart and it shows 3:73 as the highest gear ratio

you may have needed the COPO 9511 to get the 4:10

[Kurt S]

That doesn't look like a COPO #, it looks like a F&SO number. Normally something to do with special paint, but this is a 10-10 car so not a special order color. Dunno.

[chadk]

Originally Posted by JoeC

What is the rear end code? and gear ratio? is the code for 4:10?

in 1969 you can get RPO 4:10 gears but needed a COPO to get 4:56 or 4:88 for Camaro and Chevelle

For Nova you needed a COPO to get 4:10

Im not sure for Biscayne

you have to check the Power Team Chart

The axle stamp is gone as it has had ladder bars welded on and later removed and welds ground down.

I don't think this has anything to do with the gears as I have seen another Flint built L72 M22 4.10 Biscayne with nothing in the COPO F & SO boxes on the seat tag.

Thanks

[fsc66]

If it follows the same rules as the 65 Chevelle we just saw at MCACN that required a copo # or FS&O to special order a 3.73 rear axle, see attached build sheet

[JoeC]

was the other car a 1969 Biscayne or 1968?

In 1968 you can get 4:10 4:56 and 4:88 as RPO

here is the 1968 Power Team Chart
you can see where the 1969 power team chart goes up to 3:73 but the 1968 power team chart goes up to 4:88

I have been researching this because its the same for the Novas
1968 Nova can get RPO 4:10 but in 1969 you had to get COPO 9511 to get 4:10 gears

So I think Yenko used COPO 9511 to get the 4:10 gears for the 427 Novas.

Its hard to find proof on it. You need a window sticker or factory order paperwork

I do have some Nova window strickers with COPO 9511 but not for Yenko sold cars.

I think your 1969 Biscayne would be COPO 9511 for factory 4:10 gears.

Do you have a photo of the trim tag?

Sometimes the trim tags show COPO or Special order.
May be just a dash or extra numbers or letters.

I have seen COPO or Special order police or military Biscaynes that had "MEMO" stamped on the trim tag

[JoeC]

here is the 1965 chevelle power team chart for comparison

L-79 only goes up to 3:31 on the RPO

[Kurt S]

I dug a bit more and I think the F&SO code is due to the axle ratio, because it was not an RPO ratio.

[Ralph Spears]

My 1969 Corvette I ordered new COPO Special paint, has my last name on the build sheet