Sounds like Monza to me too, I know my original brakes on the front of both of the 72-73 Vega's I have are a solid thin rotor, non-vented. One car is getting the S-10 spindle upgrade, the other a straight axle.
The ball joint adapter sleeves for putting S-10 spindles on are at www.v8monza.com
. Have seen them on Ebay also.