The results of the BUN test will be contaminated if the patient is consuming certain drugs that cause problems with the blood sample. Before the BUN test, the patient should make the doctor aware of what medications are being consumed.
Vega body styles were used for several badge engineered variants. The 1973 to 1977 Pontiac Astre had Vega bodies (and Vega engines through 1976). The 1978 to 1979 Chevrolet Monza and Pontiac Sunbird wagons used the Vega Kammback wagon body with engines by Pontiac and Buick.
This worked well since the front end is wider than with the Vega spindles. I understand that 2wd S-10 axles from '82 or 83 are direct replacements for the Monza axle (7.5 ring gear) to provide the 5 bolt pattern without redrilling. My cars are '76s so they all use the torque arm and panhard rod rear suspension.