“It takes a lot of searching to find the correct candidate for a project like this,” Jeremiah Proffitt told us as we headed into the forest riding in his latest project, a 1962 FJ40 Land Cruiser.

Inspired by a Tonka truck the customer played with as a child, the FJ40 also got a series of hot-rod–inspired touches to update its appearance and performance. Key among these is a rebuilt Toyota 3F 4 ...