This photo, from May 7, 1969, depicts a bunch of techs installing a four-cylinder engine into a 1969 Pontiac Grand Prix. Yes, four-cylinder. The caption on the back elaborates.

"General Motors researchers install the combustion system-steam generator in the first modern steam car developed by the automobile industry. The experimental vehicle – called the GM SE-101 – is a modified 1969 Pontiac Grand Prix. Already mounted in the engine compartment is the 160 horsepower, 4-cylinder expander. The SE-101 is one of two steam-powered vehicles shown to the press at the GM Progress of Power show and was developed by GM Research Laboratories to permit evaluation of the vapor cycle engine under actual operating conditions."

From other resources, we see that this was allegedly the first steam-powered vehicle with a complete set of power accessories, including air conditioning, thus making it more feasible for modern vehicles.

Read the Whole Article