What year was the US White House's stable converted into a four-car garage?

Didn't William Taft do that in 1909 when he purchased the official cars for the White House? It was in that same year that the Oval Office and the Cabinet Room were added to the West Wing.

That's right Georgia.

Now for the bonus points. What kind of cars were they ?

There was a White steamer, Baker electric, Pierce-Arrow 36 H.P. landaulet, and
Pierce-Arrow 48 H.P. limousine!

Excellent