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

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

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

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

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.

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

Axle
 

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

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

here is the 1965 chevelle power team chart for comparison

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

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.

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