Only two teams – Patrick Racing and Porsche North America – used March chassis in the 1990 PPG CART World Series. Prior to 1990 Morales Motorsports closed down and Patrick Racing took over the Alfa Romeo project with Guerrero driving the No. 20 Miller Genuine Draft March 90CA-Alfa Romeo Indy V8. Patrick entered second car for star veteran Al Unser Sr. to race at two major speedway events of the year – Indianapolis 500 and Marlboro 500 at Michigan Speedway. Unser qualified 30th at Indy and finished 13th. After dropping out at Indy, Unser crashed in practice at Michigan and broke his leg. He quit the team after the crash.
| Season | Series | Event |
| 1990 | PPG Indy Car World Series | Indy 500 |
| Driver | No. | Entrant |
| Al Unser Sr. | 40 | Patrick Racing |
| Chassis | Engine | Car Name |
| March 90CA | Alfa Romeo | Miller Beer |
| Scale | Manufacturer | Collection |
| 1:43 | Onyx | |
| Cat. No. | Quality | Rarity |
| 071 | 
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