The power steering box in my 65 F100 has been converted to a later model box, which has the following numbers on it, I'd like to know what year the box is...thanks for any info you can share.
Numbers on top of box: C6AR 3580- A2 and 43 at angle...

 

P/S has been swapped into your 1965 F100, because P/S wasn't available for F100/250 2WD until 1966.

1966/68 F100/250/2WD; 1969 F100/250 2WD before serial number D96,001 available with Bendix P/S, but this is not Bendix P/S, because...

C6AR-3580-A2 is the ID engineering number for the sector shaft cover (D1AZ-3580-A replaced C6AZ-3580-A) with Ford/Saginaw P/S:

1965 and later cars, 1969 F100/250 2WD from serial number D96,001, 1970/79 F100/250 2WD & F350.

But this cover was used on many years of cars/trucks, so it's impossible to know what year the box is by this sector shaft cover ID number.

 

Thanks for the info, thought I'd post a pic which might help with a more positive ID.

 

Pic shows sector shaft cover marked with ID engineering number C6AR-3580-A2

Since Ford changed the ID engineering number and the part number for the sector shaft cover in 1971, the Ford/Saginaw P/S box is probably from a 1969 F100/250 2WD & F350 from serial number D96,001; Ditto 1970.

Ford changed the steering wheel in 1971, has 2 spokes using a horn bar.

1961/70 F100/250 2WD; 1966/70 F100 4WD; 1967/70 F250 4WD; 1969/70 F350 have a 3 spoke 17" diameter steering wheel using either a horn button or horn ring.