Topic: Identifying Small and Large Bearing Ford A/C Pulleys 1968-73

[krelboyne]

Many times the large and small bearing difference does not come into play. However, starting in 1970, Ford went to a larger diameter bearing on their air conditioning pulleys, both fixed and adjustable. Most of the 1970 and later pulley assemblies for A/C have a casting number stamped onto the brackets.
The adjustable pulley is easy, 1968-69 versions do not have a stamped casting number and uses the small bearing for the pulley.
Starting in 1970, that adjustable pulley was stamped D0AA-8A617-_, Ford also used 2 different pulleys, a one piece design, and a two piece design. Have also found several different dust caps for the bearing too.
Picture shows both versions of the adjustable pulley, the large bearing on the left, shown with a nickel, small bearing pulley on right with a quarter.

[krelboyne]

The 390 and 428CJ version of the Ford fixed idler pulley from 1968-69 has a small bearing, Ford part number C8AZ-8678-B, but not stamped with a casting number like the small block versions. Photo provided, with permission, by Bob Gaines.
The FE version of the Ford fixed idler pulley starting in 1970, has a Ford part number of D0AZ-8678-D (also without a casting stamp) and got a larger bearing for the pulley. The other photo shows the two piece pulley design, there is also a one piece version of the pulley.
Unfortunately the pulleys are not interchangeable on the two different brackets. The shaft is a different diameter for small and large bearings. About 0.596" inside diameter on the small bearing, and about 0.674 for the inside diameter on the larger bearing.

[70cj428]

Hi Scott, got a question,

I have an August, 1969 Dated NOS engine side AC kit I was going to use for my 70 CJ AC car. The fixed Idler bracket is present but it doesn't have a pulley or bearing, just the hole where they mount, and the instructions enclosed show the bracket with no pulley. Is this a 69 vs 70 thing or something else.. The kit was intended for 1969 390 Mustangs .....  ( I was told ther was no kit available for 428 cars ...)

John

[Bob Gaines]

Hi Scott, got a question,

I have an August, 1969 Dated NOS engine side AC kit I was going to use for my 70 CJ AC car. The fixed Idler bracket is present but it doesn't have a pulley or bearing, just the hole where they mount, and the instructions enclosed show the bracket with no pulley. Is this a 69 vs 70 thing or something else.. The kit was intended for 1969 390 Mustangs .....  ( I was told ther was no kit available for 428 cars ...)

John

Not Scott but It is the same bracket regardless of if 390 or 428. Yes it is meant to have a pulley on the fixed bracket. I have had a lot of those kits over the years and the all typically had just the bracket with no pulley . You can find a more common adjustable pulley and then press out the pulley and bearing. You re use the pulley and bearing to install in your bare plate.