This week’s Encyclopedia Hoonatica entry changes things up a bit: we’re not looking for cars, we’re looking for engines. Specifically, we want motors that were available in both single-cam and twin-cam versions, either concurrently or a design that was revised over time. What we don’t want are engine designs that were simply replaced with a different one of similar size from the same manufacturer. These should be different versions of the same basic architecture. As always, remember to read the existing comments first. Duplicate mentions are bad form. DIFFICULTY: Some low hanging fruit, but overall one for the gear geeks. 40,000 points for naming an engine with OHV (cam-in-block) and DOHC versions. IMAGE SOURCES: Wikipedia, hotrod.com
By Peter Tanshanomi
Tanshanomi is Japanese [単車のみ] for "motorcycle(s) only." Though primarily tasked with creating two-wheel oriented content for Hooniverse, Pete is a lover of all sorts of motorized vehicles.
Kamil Kaluski 
Jeff Glucker