Leland had been around for a long time and was advanced in age when they decided to take over the defunct Henry Ford Company. He had worked for Brown & Sharpe and Colt so he was well acquainted with precision measuring instruments and manufacturing. Leland & Faulconer and the Dodge Brothers both made parts for Ransom Olds. They were involved in engine manufacturing as well since they had a foundry of their own. Henry Ford had gotten a good start in setting up the plant for the Henry Ford Co (HFC) before he had a falling out with the money men. The equipment worked well for the manufacture of the Cadillac cars that followed. There is similarity in Oldsmobile, Ford, and Cadillac engine design due to the buy out of HFC and their previous work for Oldsmobile and the Detroit Automobile Company. The Dodge Brothers supplied Oldsmobile engines as well so they had similar patterns.
This link has a photo of Leland & Faulconer Manufacturing turning out engines.
http://www.loc.gov/pictures/item/2016816767/
This one is better:
https://www.shorpy.com/node/17496
This one has illustrations of the Model B and some of the model A & C design 2-cylinder engine for those that haven't seen them.
http://www.mtfca.com/books/1904.htm