Andy shared this boat (a Hacker) that sports a Willys 4 cyl engine. Unclear whether it is an L-head or F-head.
https://nh.craigslist.org/boa/d/milton-wood-project-boats/7543342274.html
“Early 18′ Hacker design 2 cockpit aft, engine forward 4- cylinder Willys $8,500.- 1935 18′ Chris Craft model 301 split cockpit Gray Marine 4 -cylinder $4,000.- 1949 18′ Ventnor with Chrysler 6 -cylinder. $1,500.- Hacker and Chris are in N.H the Ventnor is in Ct.”