No, it was not possible to order a Buick Regal with a 350 engine in 1985. In that year, the available engine options for the Buick Regal were the following:
3.8-liter V6 engine: This was the standard engine for the Buick Regal, producing around 125 horsepower.
5.0-liter V8 engine: This engine, also known as the 307 cubic inch V8, was an optional engine for the Regal. It produced approximately 140 horsepower.
The larger 350 cubic inch (5.7-liter) engine was not offered as an option in the 1985 Buick Regal. The 350 engine was available in other Buick models, such as the Buick Riviera, but it was not offered in the Regal lineup for that particular model year.